Database Users

XPeria Poor/Fluctuating Signal and GPS Solution

Looking at the results of the xda-developers pool I decided to get an XPeria as it clearly out shined all other phones. I got X1i this Saturday and was shocked about the poor signal strength. I was so looking forward to using this phone and keeping it but was more inclined in sending it back. Now after a couple of days just browsing the developers site which I am used to as I had an artemis before this. I see this was not the last of the problems. There have been mentions of overheating and GPS lag as well as the WIFI being rubbish. I have found the following problems
1. Signals fluctuating and mostly no service when in hand even in some good reception areas. Normally on H when in the carry case but switches to G as soon as held in hand.
2. GPS is frustrating. My artemis used to lock within seconds while having an upto date ephermis file. But even with AGPS and recently downloaded ephermis file, I had to wait over a minute to move off. It locked and then it lost and then it locked again(This was when it was in my hand). Once locked it was stable. It was on Google maps by the way.
Right for these, I have found a temporary solution and we have to work on it to make it a standard solution for all X1. Apparently the signals definitely fluctuate when you touch the lower metallic part on the back which has SE logo on it . The opinion on the forums here is that it may block the signal. I think otherwise as I have covered that area without touching the panel with my hand and there has been no signal drop but as soon as you have the slightest bit of flesh on that area the signal drops at least two bars. This led me to believe that there is an electric conduction or possibly u earth the antennas as they seem to be touching that panel from inside as it has been pointed out before.
So simple test was to put a cling film on that part and then test so I did and walah!! There was no signal drop and it worked flawlessly. I think it’s the same problem with GPS as well.
Now I couldn’t carry on using my phone half mummified. I had to take the cling film off. This is possibly the solution to everyone’s problem but I need someone to suggest either a plastic cover for that area or some sort of coating which does not conduct electricity. I think that will definitely sort the problem.

I think you've got a faulty X1 there mate..
Can you take it back to a store and compare it against another one?
The signal is weak on this compared to some other devices, (it's not as bad as the vario though), however I've never noticed a drop in signal by holding it, so I suspect somethings awry with the one you've got..
GPS signal is very very good with the later radios, what version have you got?
I get a lock within 2 seconds (8 seconds from hard reset or flashed a new rom), and it's very very accurate when it does lock.

My GPS works very well (better than htc cruise) also with previous radio.
So I think you have a fault X1, like say by fards.

I'm with Fards on this, I don't get issues when holding the phone and GPS is snappy.
crabby

Thanks guys. I know it has been discussed a million times before but I have compared the phone with other XPerias and it is the same. There are atleast 4 threads pointing out the same. My X1 would have better signals than my artemis as long as i dont touch the back base. Have you all got silver X1is? If so then can you check if you touch the back panel which i mentioned, if there is any fluctuation in the signals(its not instant it takes about 10 seconds for the phone to show the loss of signals).
I have updated radio to 55 and tried the two new stock roms which are R2A for O2 and 010 generic. The phone still looses signals but not completely when i touch the back panel.
About GPS, it does get a lock very quickly but looses it for a short while when i touch the back.
Anyway if someone else comes accross the same problem then please write here as I am sure there is a solution to be found. I was looking at the following
Clear coating
Antistatic spray coating

I must have missed those threads then.
I have a black x1, and definitely don't get any of those issues.
gps is steady and strong.. monitoring it now... as I type. 6 birds locked standing next to window in house hdop 0.6m which I think is very very good
gsm signal on 2 bars and steady

I had the same issue just once. And even when X1 was in the Brodit car holder.
In my case the soft reset was sufficient to solve the problem. But I guess that you already did that.

fards and pelriog? did you experience any fluctuation when touching the panel?
These are the links to threads
Thread1
Thread2
Thread3
Thread4

Same here, touch back panel, hold for 10 secs and signal drops 1 bar. Currently on 3G network, going from 2 bars to 1.
(And yes, my W810i gets a way better signal in low coverage areas. However, usually not a problem, since I hardly encounter Vodafone low coverage areas in The Netherlands).
Tested 5 times. Dutch Vodafone X1i, R2 stock ROM & stock radio.

Ok I did the touch the panel thing and my bars increased by one... hmmm perhaps there is another faulty batch out there as I get great signal (touch wood) and my gps is very responsive and accurate...

Silver X1 here.. Been touching it up for about 15 mins now
It does seem to drop by 1 bar when touched, but also drops if i just put my hand really close to the back without actually touching. hmm..
what concerns me more is how it just drops the whole line randomly and gives an x then has to search again. Lost a good few calls from that..

well here ive got no problem at all with signal.
But GPS does suck even though most people everywhere say X1 GPS is awesome.maybe it is just my zone/country.. could that be possible?
uhm.. of course not, their satellytes afetr all.

I have disassembled my X1 myself and found that under lower part of backside (piece that have SE logo) is an antenna of some kind.
The antenna is a thick circuit that ran on top of another piece of plastic that cover the loud speaker.
The circuit only have 2 contacts to the main PCB.
My guess is that the reception site of either GSM or GPS is on that part.(may be bluetooth or WiFi too, but I think that's not it)
I wonder what SE/HTC engineer is thinking, putting antenna on this part of the phone! (covered with my hand everytime I use it!)
The solution is "use bluetooth headset" and "hold your phone upside down" and you will be fine.

Yeah, mine loses a bar when touching the metal case at the back, I've not lost any calls (that I know of) because of this though.
I had a look under the speaker section myself last week, and can confirm the antenna circuit over the speaker section. Underneath there's also what looks like a tiny external antenna socket... we could mod our experias to have a rubber duck aerial? Who's up for walkie talkie lookalike xperia?

lol @ walkie talki and upside down. I think the designers have done a very poor job as far as the antenna location is concerned.
Tumpin does your phone loose all signals when in your hand?
Taking this seriously as suggested in my first post has anyone tried putting a cling film on or to that matter anything to cover that area and holding the phone. I did it with the cling film and there was no drop in the signal. So i think it is just a matter of us using some kind of invisible coating or cover on that area so there is no static conductivity. Look at post #5
I would appreciate if everyone gives there suggestions as well how to deal with it. For the people who took the phone apart you could have put something on the inner side to block the static discharge.

I returned my xperia for the second time for signal problems. The problems started after it was repaired for the crack in my case. After that the signal was very poor. GPS was not working in 90%. I wait for 15 minutes for signal, but the only thing that happend was heating the battery. Also HSDPA have a weak signal. In most times I only can use GPRS. The first time I returned the phone for this problem nothing changed. And this time I had a new crack in my case, so I hope they send me a new one!

Im using a X1a and I find its GSM/3G reception is really poor, I already upgraded the radio to the latest but its still the same poor poor reception. Specially when Im using the metal case I frequently get drop calls on my device

kanthai said:
I have disassembled my X1 myself and found that under lower part of backside (piece that have SE logo) is an antenna of some kind.
The antenna is a thick circuit that ran on top of another piece of plastic that cover the loud speaker.
The circuit only have 2 contacts to the main PCB.....
Click to expand...
Click to collapse
Just curious! Any chance that you see what for are the two metal plates contacts from the metal cover of the phone? Those near the SE logo. These two and the other two towards the camera are there for... what? The metal cover is used for something as when you rig in the phone and all four contacts are "online" but what for? Thanks!

I have a black X1i and noticed that reception increased when using it with the keyboard opened in horizontal position.

Same here, I tought it was because I open my metal case that is why reception goes up.
stevencyc said:
I have a black X1i and noticed that reception increased when using it with the keyboard opened in horizontal position.
Click to expand...
Click to collapse

Diamon2 T5388++ NEW GPS reception fix

EDIT: DISREGARD THIS. GO TO POST #3 and #4
Hello guys,
this is my first post so if I'm posting in the wrong section please bear with me.
I recently bought a T5388++ HTC diamond 2 clone. Everything was fine except that I couldn't get a GPS fix. (In the Start -> Settings -> System -> GPS Settings [Satellite State] I only had *red* satellites)
I used the "aluminum foil in the back side" fix, which worked well and I could get a fix.
Being an uneasy person I open the back cover of the cell phone to take a look (beware the headphone cables).
Now here is the good part.
On the left side (near the sd card and where the stylus ends) is probably the GPS antenna.
In the inside, on the board's side, there are two metallic "pins" which (when the cover is closed) touch the back of the antenna. What I did was to add some foil on the back side of the antenna so the contact with the pins would be more tight.
This worked like a charm and the signal is very good. I can even get a decent fix (3-4 *blue* satellites) from inside the house.
Sorry for the lack of pics, if anyone tries it, post a couple pictures and I can show you what I did exactly.
EDIT: DISREGARD THIS. GO TO POST #3 and #4

Pics!!!!
Here are some pics.
First unscrew the four screws, one at each corner of the phone.
Then slice the phone with the help of small flat screwdriver or some other tool. (there are some appropriate notches for that purpose)
**Beware of falling parts**
In the forth and fifth pic you can see where I install the alu foil.
Now you can close the phone and enjoy your newly found GPS!
[I also tried some solder, but the results where almost the same]

Congrats.
However, I can assure you that is not the GPS antenna. Based on the antenna size and shape (its a small inverted F antenna, see the black sticker that is attached to in on top of the stylus case) I am assuming it is either the Bluetooth or WiFi antenna.
The GPS antenna is a bit higher, it is the small pink 'cube' thingy on top of the phone, connected by the micro coax connector.
I had reported before the micro coax is loose in some devices, and I suspect you 'accidentally' fitted it better while opening and closing the phone.
But congrats on your successful operation anyway, being able to open and close the phone and still have a working one is already good, and often, just doing that and ensuring all connectors are clean and properly fit solves a all sorts of problems.

Yeap you are right!
I have read you saying this about loose connectors, so when i first opened the phone I refitted the micro coax.
In my defense I tried to see if this was the antenna. I disconnected it and opened the GPS. Seeing many satellites on the screen (red ones) I concluded that this was not the GPS antenna. (I thought maybe WiFi since I've seen this type of connector on my laptop's wifi)
But having read your post now, I tried a new experiment and found out that the "red" satellites appear, due to the A-GPS (with neither "my" GPS and THE GPS antenna).
Damn...
So could someone change the title to "OLD GPS reception fix"

I had the same problem with GPS. I have risked and have changed orientation GPS of the antenna - GPS perfectly works. BUT now the speaker in which I hear the interlocutor doesn't work for me. At other person after the assembly has broken touch the panel. Therefore it is better not to recommend to open phone.

onde consigo a rom do htc t5388+ idioma PTG ?

magicwolf said:
I had the same problem with GPS. I have risked and have changed orientation GPS of the antenna - GPS perfectly works. BUT now the speaker in which I hear the interlocutor doesn't work for me. At other person after the assembly has broken touch the panel. Therefore it is better not to recommend to open phone.
Click to expand...
Click to collapse
You changed the orientation of the antenna. In which way?
When I opened the phone to see if the connector is set right one cable to the speaker was dispatched (very bad soldering). I had to remove the old cable and solder another one because it was not only loose it was broken, too...grrrr...that's very bad.
But I was lucky and did't burned my phone
So, I also recommend to be VERY careful when opening the phone.
BTW: It is much simplier to open the T5388++ than my ASUS P535.

MicAlter said:
You changed the orientation of the antenna. In which way?
Click to expand...
Click to collapse
In a picture it is visible as I oriented the antenna.

cybermaus said:
Congrats.
However, I can assure you that is not the GPS antenna. Based on the antenna size and shape (its a small inverted F antenna, see the black sticker that is attached to in on top of the stylus case) I am assuming it is either the Bluetooth or WiFi antenna.
Click to expand...
Click to collapse
Can you please identify Wifi antenna? Look in attachment:
"C" is GPS antenna.
What is "A" "B" "D" ?
"D" - I see little piece of aluminum foil, but nothing else. Under this foil is place for stylus only and above foil is contact + Vibration Motor.

Somewhere I reed a tip not to hold the hand on the bottom of this phone during the phone call in order not to shield located there GSM antenna, so it means B is probably GSM. Are you sure C is BT and not GPS?

You're right. "C" is 100% GPS antenna. My mistake. (I've changed it now in original post.)

Well, my guess is B (at the bottom) is GSM, based on the fact it is larger (lower frequency) and seems to have two (one for the 850/900 MHz and one for 1800/1900Mhz), which leaves A and D for Blue and WiFi.
PS: Or GSM has two because it has 2 radio's? I wonder if they would share antenna or not, since it is a dual-sim dual standby, I guess the could share)

serak_hd2 WiFi probl.
If you have opened your phone already you can easily discover which one is wifi and BT. Just put a peace of paper on one contact (blocking connection), reassemble (screws are not necessary) and try connect to BT devise (compare to previous performance(distance)) if it is gone (or big performance difference), you blocked BT if not, it was WiFi. After you know which is Wifi, just try to ensure good mechanical contact from antenna till the board (bending contactors little higher or putting allufoil (aluminum can oxidize quickly, so it is not the best solution)). Try not to touch the board, some of the components can be sensible to static discharges. If you have not opened it yet, try to consider ones more the possibility to change it by your seller for new one.

problem with touch screen
t5388 + + touch screen does not work, but the image looks perfectly fine.
How to fix this?
thanks

cybermaus said:
The GPS antenna is a bit higher, it is the small pink 'cube' thingy on top of the phone, connected by the micro coax connector.
I had reported before the micro coax is loose in some devices, and I suspect you 'accidentally' fitted it better while opening and closing the phone.
Click to expand...
Click to collapse
I also had this problem, the connector was loose, now I have very good signal. No aluminium foil needed. Your post saved me!
My recommendation to other people trying to solve this problem: be VERY careful when you open your phone.

CORRECT Hardware GPS Fix

First off, I want to say that Plato56 was the first person to try this, and I want to give all credit where credit is due. Several others have applied this method, including myself, with great results. I apologize for not knowing everyone and I apologize if any of this is not clear. Please let me know and I will clarify the best I can and update this original post.
Ok, the other thread found here is close but the wrong contacts are circled. I've uploaded several pics to reference as you read through this post. The first pic has the correct contacts circled. The contacts circled in the other thread are for the cellular radio.
So What's The Deal With The GPS on my SGS!?
Essentially, the problem is two fold.
Problem #1: Samsung has no clue how to put out decent firmware.
Problem #2: The copper contact that Samsung chose to connect the GPS Receiver to the GPS Antenna is about the crappiest selection they could have possibly made.
THE PURPOSE OF THIS THREAD IS TO ADDRESS PROBLEM #2. If we address and solve one then we can (hopefully) tackle the other effectively one day. Here is a technical, but relatively easy to understand explanation of why Firmware alone can't fix the GPS problems that plague ALL SGS phones (even if your GPS is "fine" it still has weak SNR Numbers)
Explanation (Courtesy of T313C0mun1s7):
Q) Is it hardware?
A) It's complicated. We are talking about very high frequency RF here, you gotta understand how electricity acts when you reach these frequencies to fully get this, but I will summarize. At zero hertz or DC current electricity flows through the body or center of the conductor. As long as you have enough conductor to carry the required current you are good. So the type of spring contact they used is fine for DC, in fact I went looking for replacement contacts and the only thing I can find are designed for either battery tabs or for grounding contacts. As you go higher in frequency the AC current of electricity takes on what we call skin effect, it travels as waves around the surface of the conductor. For this reason large diameter, low loss coax usually has a hollow center conductor. It make no difference electrically and makes it more flexible, lighter, and less expensive because it saves copper. Connections have to be solid and shielded because the RF can "leak", noise can be introduced, and the conductor should be tuned to the frequency carried. In short, these spring connectors are about as bad a connection as you could have picked. It is not enough that they touch the pad, you need good solid contact for a good transfer with the skin effect and to minimize loss. It seems that this problem is exasperated by poor contact. This fix it to simply improve the contact by increasing the pressure and hope to minimize the ill effects of this poor choice of contact design. To complicate things there are in fact things that can be done in software to improve the situation - this made trouble shooting harder because people tend to see these things as black and white and therefore either hardware OR software. If you want to know how software can affect this, then you will need to read back through the thread as I have already explained it twice and this answer is already too long.
Q) Should I ever expect a fix?
A) Read the OP. It was "fixed" (ie they improved the connection, but they did not re-engineer a proper fix) already. It seems if it was made in September there is a good chance it is ok or marginal. If it was made (or possibly re-manufactured?) in October it seems they are at least as good as the fix we are applying in this thread. Either they are using better contacts or they are increasing the angle to apply more pressure.
Q) Will T-mobile replace it?
A) They recognize the problem. This is what the app Samsung released is for. It resets everything to the stock settings (and nothing else). If you use it and can show unacceptable performance with the GPS (via the measurements the app makes - it is the official guide replacement), then they should replace the phone for you without any fight.
Now that you know why you should consider applying the hardware fix to your SGS, read on to determine if it may actually help your situation. I.E. does your unit's manufacture date and/or modem make this modification worth your time?
Prerequisites (Courtesy of T313C0mun1s7)
If you don't yet have at least JI6 then you need to be at least at that modem level FIRST. If you are already using the JI6 (or newer) modem and your GPS still sucks AND your phone was manufactured prior to October, then try this. Otherwise don't expect results. To determine your manufacture date, look on the box. If you no longer have the box, then look under the battery. The middle line has the serial number marked with a S/N. To the right of that will be a set of numbers with a period in the middle. It is month and year in European format, so 10.09 would be September of 2010.
To summarize:
* Phone made in October 2010 or after - this should not be needed
* You have not upgraded to at LEAST JI6 - then do that FIRST
Steps To Apply The Hardware Fix:
NOTE THAT THIS TECHNICALLY VOIDS YOUR WARRANTY especially if you choose the alternate method that involves a soldering iron
However, there is nothing noted on the phone that says if you remove this or go beyond that your warranty is voided.
Also, as goes without saying, don't blame me if you snap your GPS Antenna Contact off, break your plastics, or lose the ability to procreate!!!
* Turn off your GPS and shut down.
* Remove the back of your SGS and take out your battery, SIM Card and MicroSD Card.
* Remove the 7 screws that hold the back plastics. All you need is a Philips Head screwdriver from any jeweler's kit or glasses repair kit (you can get one from CVS/Wal-Mart, etc). Here is a video that shows you how to open up your phone. Take your time with this. I know it seems unsettling at first, but everything will be OK as long as you take your time and use a little common sense!
Be sure to watch for three small things after you get the back off. If you aren't careful, all three will sprout legs and run away :
1) Volume Rocker
2) Power Rocker
3) A little round plastic circle next to the lower right of your SIM Card slot that may fall out
* Refer to the 3rd and 4th pictures I uploaded (courtesy of androidmonkey). These photos depict the CORRECT CONTACT to gently bend up. The 4th photo depicts the position your contact should be in. You'll probably find that yours is laying flatter and thus isn't making contact with the GPS Antenna (which is on the plastic backing that you removed). As I said a second ago, gently bend this contact up. I used a flathead screwdriver from a glasses repair kit. It doesn't take much bend this contact. I started from the side that the fourth photo depicts. After I got the contact up a bit, I moved my screwdriver over 90* where the hump is and pried a little more. That's it! It's really simple. Just don't go happy with your bending. I have no experience replacing a snapped piece of copper so I can't be of any help if you destroy yours.
* Button everything back up. The back plastic will pop back in 10000% easier than it came off. Put the screws back in, pop your SIM and MicroSD back in and your battery. When you boot back up, you might wanna clear your GPS settings just for the heck of it. I did. DO NOT be shocked if it takes a few minutes to get a lock. It's probably the first time your SGS has ever had a real chance at a lock. Subsequent locks (Hot and Cold Start) will be faster.
* Boot up, leave your GPS off. Just because it can't hurt, clear your GPS settings. Here's how:
1) Download this app http://forum.xda-developers.com/showthread.php?t=775154
You can find it by searching for "sgstools" in the market. Click on Secret Codes then Lbstestmode. At the bottom you'll see "Delete GPS Data". Just click that!
OR
2) Open your dialer and hit *#*#1472365#*#*
Click "Delete GPS Data".
* Turn your GPS on. Wait for a lock! If you want to know what's going on, download two apps:
"GPS Status & Toolbox" by EclipSim
and
"GPS Test" by Chartcross Limited
That's it!
ALTERNATE METHOD - ADDING SOLDER TO YOUR GPS CONTACT
*WARNING* As I mentioned earlier IF YOU CHOOSE THIS METHOD THERE IS ZERO CHANCE OF YOUR PHONE REMAINING UNDER WARRANTY *WARNING*
If you feel inclined to modify your phone in a much more permanent way, you can opt to add some solder on top of the contact (no need to bend the contact up, in fact, don't). I attached a zip with some pics that show what two posters, regp and Mannymal did. I've soldered a few things in the past, but I'm by no means an expert. If you choose to do this, a few things to remember.
* First, seriously consider avoiding this if you have no experience with a soldering iron. In what I've seen on a limited base, you'll get minimal SNR gain in return for the effort that goes into this. I can't emphasis this enough.
* There are probably a 100 tutorials on how to solder floating around on YouTube, watch them (all).
* The absolute largest diameter solder I would use is .022.
* Find the smallest tip possible.
* Heat the CONTACT with your soldering iron, not your solder, or you will create what is called a cold solder joint that will probably lead to your GPS not working at all on down the road. You have to get the contact hot enough to receive the solder, which is touched to the part (in our case, the contact) that you want to apply the solder to.
* Be careful not to make your solder to high. I suggest looking at the photo that shows the angle of the contact after it's been raised and using that as your benchmark. We want to make contact with the GPS Antenna, not break the thing when we snap the back plastic on.
* If you end up with two much solder you can either clean the tip of your soldering iron and touch the hot tip to the solder to remove some or you can use an emery board to file it down.
* Use an small emery board (nail file essentially) to file down and smooth off your joint. I suggest doing this holding the phone upside down so you don't end up with 1000 tiny solder particles floating around your phone.
* REMEMBER, phones are tiny. These boards are tiny. A soldering iron that is too hot left on ANY board for too long will destroy it. Multiply this rule x10 for delicate parts.
Good luck.
Observable Data Changes
(Grabbed from this thread after several days of playing with this fix).
Accuracy: 16-28 feet stationary 38-50 feet moving (moving accuracy has improved and is now on par with stationary numbers since I started running the Stock JL4 Rom)
Average SNR: 22-35. Obviously you'll always have one or two that are lower and one or two higher. My max I've observed was 42.
Number of Sats Locked/In View: 8/11 most of the time. Yesterday afternoon I was locked on 10/10 with a 22 foot accuracy inside. I've had 11/14 before as well, just depends on the time of day.
Cold Start Lock: 30 seconds
Hot Start Lock: 5-15 seconds
For reference, my Garmin Nuvi is currently connected to 7/10 with a 16-18 foot accuracy and my Vibrant is connected to 7/10 with a 21-25 foot accuracy. (stationary of course)
Unnecessary re-routing: No
Wandering on Google Nav/Lost Signal with Nav: Very rarely. For me it happens when I lose signal which is only if the phone is resting on my jeans. If it's in my cupholder, center console, hand, etc it's fine. Earlier today I lost signal with it in my cupholder but I was traveling in an area where my Garmin Nuvi only had a connection to 5 satellites.
My Tracks: No data from me yet
There are some after screen shots in this post.
Other notes: I'm on the road a lot. Today is my first day to really extensively test it. Basically, it's MUCH better. Is it perfect? No, but I will say that unlike these other fixes that involve changes in lbstestmode and reset apps that only last for a couple of hours at best, my GPS performance has been very consistent ever since I adjusted the antenna contact. Is it as good as my old Blackberries with signal strength? No. How does it compare to other Android devices? I have no clue.
What I do know is that it works well enough for me to be comfortable not having to grab my Nuvi everytime I switch vehicles.
Click to expand...
Click to collapse
Wrap Up
I hope this works for those of you like me that have tried almost every firmware update, tweak, etc. Between this fix and JL4, all I can say is that this device is probably as near to perfect as it'll ever be. I've been running this fix for well over a week and I've experienced no signs of the modified contact losing it's contact with the antenna.
If You Still Have Problems
* Even though you used the Samsung GPS Restore App (Found in the market for Vibrant/Captivate only)
* Even though you deleted GPS Data
* Even though you have your WiFi Off like Plato56 recommends in this post
* Even if you tried a full system wipe
Don't panic if you don't have a ton of locks. Like mentioned above, there is still a firmware component to this issue. I see times where mine doesn't want to lock. Usually if I turn GPS off and then turn it back on it runs smoothly from there on out. Depending on where you live, time of day may make a difference. Inevitably, in the afternoons I may only get 6 of 11 locked on. All other times I can get 9-11 of 11 or 11 of 14, etc. Bear with it. This fix is NOT a silver bullet, but give it a day or two of reasonable playing time to determine if it helped.
For example, right now I'm indoors locked on 7/11 with a 21 foot accuracy and SNR's averaging 31. I used to see 0/3 with SNR's averaging 29. That's a definite improvement. If any other Android was in the same position it would probably show 8/11 with a 10 foot accuracy and SNR's averaging over 65.
So take it for what it's worth, but the fix is DEFINITELY worth the effort!
ADDITIONAL TWEAK
Check out this thread here and read through the OP carefully. A few days ago I flashed "S.gps.zip" and I've had great results with it on Bionix 1.3.1 with the KA7 modem. I didn't see an increase in accuracy, but I did see a HUGE improvement on the speed my GPS locked and the number of birds locked too. I played around with all of the 2.2 modems last night and they all saw improved results.
If you decide to flash one of those zips, I recommend making a Nandroid backup first. In reading through the thread it appears that there are a few people that had their flashes result in broken GPS's. I have no idea why, I'd imagine it's because they didn't clear GPS data and they just think it's broken. I recommend making a backup, shutting off your GPS, booting into CWM, flashing the zip, rebooting, clearing GPS data, turning your GPS on and enjoying locks. And, as always, I recommend using GPS Test by Mike Lockwood to test your GPS every time you make a change.
The Super GPS should work on any ROM on an Vibrant, but it looks like a lot of people have tried it on 2.2 ROMS so be aware that, as always, there's the chance you may brick your device. If it works for you, be sure to thank jellette for his work. As always, I take no responsibility if this messes up your phone. I'm just relaying what worked for me.
UPDATE: 7/31/11
I should have posted this a couple of months ago. I also have a theory about why sometimes this fix fails over time. For example, I run Overstock 2.4.1 and I often flash the S.gps2.zip when I redo my system. It's been a fantastic combo on Bionix 1.3.1, but often, after a few weeks my GPS begins to turn retarded and will eventually no longer lock. In the past I've always believed it's purely because the antenna contacts have started to relax. However, what I've discovered is that when I go back into CWM and reflash my kernel and reflash the GPS zip, everything is happy and perfect again. I'm by no means a hardware genius or a developer. I'm just an average end user that loves to tinker with things and be methodical in testing, but I'm starting to believe that there truly is something going on that corrupts our GPS Drivers over time (in reference back to how we know Samsung screwed the pooch on firmware for the GPS Receiver).
So, that said, before you crack your phone open over and over yanking and bending on contacts, reflash your kernel and the GPS Zip of your choice. And, like I've always said before, if the hardware fix doesn't seem to work for you when it seems to work for others on the same ROM as you, try another kernel, and try it more than once. I still fully believe that every GPS Receiver on every SGS can be made usable. It's not perfect, but it's a strong improvement from not being able to obtain a lock. http://forum.xda-developers.com/showpost.php?p=16026963&postcount=12

Q&A
This thread is getting long so I am creating this Q&A post to answer many of the most common questions.
Due credits go to those that originally asked and answered these questions. Obviously this thread is the result of the efforts of many people.
Q) Is it a hardware issue? Why do different ROMs / Modems effect this?
A) It's complicated. We are talking about very high frequency RF here, you gotta understand how electricity acts when you reach these frequencies to fully get this, but I will summarize. At zero hertz or DC current electricity flows through the body or center of the conductor. As long as you have enough conductor to carry the required current you are good. So the type of spring contact they used is fine for DC, in fact I went looking for replacement contacts and the only thing I can find are designed for either battery tabs or for grounding contacts. As you go higher in frequency the AC current of electricity takes on what we call skin effect, it travels as waves around the surface of the conductor. For this reason large diameter, low loss coax usually has a hollow center conductor. It make no difference electrically and makes it more flexible, lighter, and less expensive because it saves copper. Connections have to be solid and shielded because the RF can "leak", noise can be introduced, and the conductor should be tuned to the frequency carried. In short, these spring connectors are about as bad a connection as you could have picked. It is not enough that they touch the pad, you need good solid contact for a good transfer with the skin effect and to minimize loss. It seems that this problem is exasperated by poor contact. This fix it to simply improve the contact by increasing the pressure and hope to minimize the ill effects of this poor choice of contact design. To complicate things there are in fact things that can be done in software to improve the situation - this made trouble shooting harder because people tend to see these things as black and white and therefore either hardware OR software. If you want to know how software can affect this, then you will need to read back through the thread as I have already explained it twice and this answer is already too long.
Click to expand...
Click to collapse
Q) Should I try this fix?
A) Only if you can not get your phone replaced under warranty. If you can not and meet the prerequisites in the OP, then you are a good candidate.
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Click to collapse
Q) How do I update to JI6? In the release notes of the Super_IO kernel, it mentions it has the UVJL1 modem. is this more recent than JI6??
A) Yes, JL1 is more recent than JI6. The nomenclature uses lexicograpical unicode values.
1. Check the first unit. The first unit in JI6 and JL1 are both 'J', so look at the next unit.
2. 'I' in the former, 'L' in the latter. 'L' comes after 'I' in the alphabet, so it's more recent.
3. You can stop here, because you've already determined that JL* is more recent than JI*. Any units that come after this are to distinguish within the L- or I-series.
Click to expand...
Click to collapse
Q) How do I reset the GPS setting?
A) Open your dialer and hit *#*#1472365#*#* or maybe *#3214789650# (I need clarification on these)
OR
The Samsung GPS Restore app (APK attached to this post)
OR
Since the Feburary 2nd, 2011 Market update you can find it here https://market.android.com/details?id=com.sec.samsung.GpsRestore
Click to expand...
Click to collapse
Q) Should we assume that any phone manufactured before 10/10 has these problems?
A) No, I would not think so. Something like this is usually a intermittent manufacturing flaw and would not affect everyone or there would be an even larger outrage about it.
Look at it this way. The spring contacts were designed to make contact without too much pressure when the back is properly in place. GOOD engineering would have accounted for slight variations in manufacturing and quality control and would have made the spring contacts overshoot the required distance a little to assure 100% contact in all situations. In this case I think they forgot to account for that and designed them to just touch, invariably some make intermittent contact and some fall just short of good solid contact (there are prior posts about how poor contact can get worse over time due to oxidation and arcing), but at least we have no reports of totally non-working GPS where they would have failed to touch outright. Chances are when October came around one of two things happened.
They decided to fix the issue and reenginerred the design to make better contact
The manufacturer ran out of the old contacts the the new shipment just work better
Either way, although this is a common issue, I don't see the evidence that it affected all pre-October phones.
Click to expand...
Click to collapse
Q) Any hints on how to get the back off after removing the screws? I watched the YouTube video, but I'm not having any luck with my normal sized fingernails.
A) It is very stubborn, the most important tool you have is patience. Just take your time. If you really need more than just you fingers here are some other options.
Set of Safe Open Pry Tools - http://www.repairsuniverse.com/prytools.html
Thinner than credit card type cards such as a Bi-Mart membership card, plastic business cards that are 1/2 thickness of a credit card, laminated ID badge, old Subway rewards card.
Guitar Pick
The plastic from a clear "clam shell" type package that everything seems to come in now. You know, the ones that seem impossible to open.
Click to expand...
Click to collapse
Q) CRAP!!! I BROKE MY TAB (This question covers Soldering)
A) Relax, take three deep breaths, all is not lost.
What you want to do is replace the tab with a small mound of solder to bridge the space between the boards and create a contact so the two pads touch. You want a decent amount of surface to touch and you want it flat for the best contact. You need the mound smooth and round because you are working with high frequency signals. Follow the instructions below carefully. If you need more details they are in this thread.
1) If you are experienced in soldering most will be second nature to you except for the fact that you are not actually soldering anything to anything, you are just making a mound on a pad. If you are not experienced then the first step is to WATCH THESE VIDEOS (A) and (B) then PRACTICE until you are proficient in the basics of heating, soldering, and removing the iron cleanly leaving a good joint.
2) Read this comic book (trust me) --> http://mightyohm.com/files/soldercomic/FullSolderComic_20110409.pdf
3) Now if you are confident that you are ready to actually touch a hot soldering iron to the inside of your phone lets continue.
De-solder the old broken contact from the pad using the soldering iron and either some wick or a solder-sucker (you can also use a cheap rubber bulb, but they rarely work well)
Use the soldering iron and wick or solder-sucker to remove any remaining solder from the pad. It can still be silver, but should be flat.
Realizing that you will remove a little solder with the iron when you pull it away, make a small, smooth, shiny, and round mound of solder on the lower pad just a little taller then you need for good contact.
It is important in this step to not leave any metal filing behind on the board or it might short something out. So do this step holding the phone upside-down so they fall away. File the top of the mound with an emery board so you have a flat spot parallel with the pad. Don't file too much at first.
Check the height of the mound by puting the top board back on. If needed file a little more and recheck. Go slow, don't try to take too much off at once. When the hight is right it should just barely be too tall. You want good solid contact, but you do not want the board to be stressed or bend.
If all looks good check again for hidden shavings and blow it off real good just to make sure.
If you mess up at any point just de-solder the pad and try again.
Click to expand...
Click to collapse
Q) What are people's setting in LBSTestMode?
A) Factory Defaults - an earlier question covered how to get back there
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Click to collapse
Q) Will this work with the GT-I9000 or the Captivate?
A) Most likely, yes. We have even had some people with those phones report back with positive results.
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Q) I did this hardware fix, but I am still losing locks. Now what?
A) Here is what the OFA (Original Fix Artist) Plato56 has to say:
1. Before anything else, make shure your WiFI radio is OFF. I dont mean not connected, I don't mean out of range, I mean hardware swiched off threw your settings or via the drop down status bar.
2. Use the Samsung GPS restore to get you LBS settings to default.
3. Update your modem to one of the 2.2 versions. Im particularly happy with JL4 modem myself
4. Learn to use ODIN!!!! Use this to reload your firmware of choice. Prior to flashing you favorate ROM, Always flash back to JDF (BONE STOCK FIRMWARE).
5. If you dont know what im talking about in 4, then go to the developers section and read, read, read.
6. If you have any other questions refer to sujection 1 first, then ask. Honistly, alot of people have put some work into verifing if this fix works and testing with various software, the least you can do is read this body of work and you just might end up with a working GPS.
7. My last tip of the day. Be patent with your first locks, the GPS does improve the more data it collects. This also means dont delete your GPS data unless you changed modems or are having real lock and or accuracy issues
Click to expand...
Click to collapse
Q) Does this fix drift?
A) There have been a couple that have mentioned that it does fix the drift, but I think there may have been others that say they get better locks but still get some drift. I do believe though that everyone who has done the driving test with it has reported that it tracks better now and actually shows them on the correct roads, where before it didn't.
Click to expand...
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Q) What are the other contacts?
A) Opposite side is Wi-Fi, bottom is cellular.
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Q) OK, so I can bend it up, or replace it with a bit of solder. Is that all?
A) Of course not. Some like to stick a little piece of plastic under the tab rather than try to bend it. Just a little sliver about as wide as the contact cut off a credit card should work. Your Mileage may vary, in my mind if you drop the phone that plastic is gonna be floating around in there somewhere.
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Click to collapse
Q) So inside I see. . .
A) Stop! go outside. GPS was not designed to help you get from your bathroom to your kitchen. GPS signals are low power signals that have to travel all the way from an orbital satellite. Low frequencies penetrate well, and bend around objects, but they require a lot of power to transmit over distance. High frequencies travel much further with less power and remains in a fairly strait line, but it does not penetrate very well. Guess what GPS uses. So don't make it try to penetrate your roof.
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Q) So there are two apps listed to test GPS and . . .
A) I've noticed a big difference between the two apps called "GPS Test". Try using the one written by Mike Lockwood (he's on the Google GPS team).
http://www.androlib.com/android.appl...stest-qjx.aspx
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AND FINALLY
Q) What does tonight taste like?
A) Tonight tastes like chinese food and whiskey with coconut water
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Click to collapse
A final note about satellites and tracking said hunks of orbital equipment
I have noticed a lot of people are wanting to compare signal levels. This is fine on a superficial level, and there should be some level of consistency as long as you live on roughly the same latitude as the person you are comparing with. As Einstein said - everything is relative. With that in mind I thought I would share a post I made in another thread. There is cool stuff in here - so check it out.
T313C0mun1s7 said:
Another thing that you have to realize is that the satellites themselves are a variable. The only way to make a satellite stationary is to put it into orbit directly on the equator, falling at the exact same rate the earth spins, and in the same direction. Even at that there is still a little wobble in a figure 8 pattern.
So GPS sats are anything but stationary, but they are flying at great speeds overhead coming in and out of view by their own rite at any time. At the speeds they fly the distances to you change by the mile rather quickly. So it should be no surprise that doing your testing repeatedly will never yield the same results twice. There are also a lot of other factors involved as well.
The point is that you are now getting very acceptable and usable results from your GPS consistently, even if you never get anything as great as your first time. Maybe you will get those strong of signals again, but even if you don't you seems to be an par with what the majority of people have reported so far.
FYI - If you would like to see some real time tracking of GPS sats that you should be able to see (THIS IS REALLY COOL) go to http://www.n2yo.com and click the GPS link at the top of the page. It will load a page of sats that are visible from your location. Click the select all box and then click the track selected satellites button. It will load a world map with the orbital paths of the sats, then the sats themselves. You can watch them move and even select them for more information on each satellite. This is not limited to GPS satellites if you want to keep playing with it. The point is that if you watch it for a little bit you can see pretty quickly as they move relative to the world map they are on just how many miles (or kilos) they cover in a fairly short time.
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Great Post
I have been looking for this information everywhere. I cannot wait until I try this. Thank you^^

How do I update to JI6? i'm running Macnut 14 rom with the Super_IO kernel.
In the release notes of the Super_IO kernel, it mentions it has the UVJL1 modem. is this more recent than JI6??

This might be a stupid question, but how do you tell the manufacture date of the phone. My box just has a date on it (but doesn't say what that date is for), which is 08/10/2010. Is this it?

salvador3 said:
How do I update to JI6? i'm running Macnut 14 rom with the Super_IO kernel.
In the release notes of the Super_IO kernel, it mentions it has the UVJL1 modem. is this more recent than JI6??
Click to expand...
Click to collapse
Yes, JL1 is more recent than JI6. The nomenclature uses lexicograpical unicode values.
1. Check the first unit. The first unit in JI6 and JL1 are both 'J', so look at the next unit.
2. 'I' in the former, 'L' in the latter. 'L' comes after 'I' in the alphabet, so it's more recent.
3. You can stop here, because you've already determined that JL* is more recent than JI*. Any units that come after this are to distinguish within the L- or I-series.
Just gently bent my piece of metal up. Giving it 10 min to find satellites and will edit this post to report.
EDIT: HOLY CRAPOLA! In the time it took me to write this post, I got 11 satellites on a cold start, MS based, with supl.google.com. I'm going to keep it on hot start now that it's got some locks. I've never run a GPS test at my current location (indoors too!), but I usually got 1 or 2 about 30 miles south of here (outdoors). I can't verify that it's the alteration that helped, but my GPS is definitely better now. Much thanks to OP.
RE-EDIT: Huh, this is weird. I tried to exit out of app but it froze. Waited a minute and it exited out, but without the expected transition animation. Tried to open it again, but the GPS icon in the notification bar wasn't flashing so I rebooted. Now I don't get any satellites with the same settings as before. A couple reboots later, everything is going according to plan.

salvador3 said:
How do I update to JI6? i'm running Macnut 14 rom with the Super_IO kernel.
In the release notes of the Super_IO kernel, it mentions it has the UVJL1 modem. is this more recent than JI6??
Click to expand...
Click to collapse
If ur running a 2.2 ROM u are past JI6....
Sent from my Vibrant w/ Onyx 4.2 Overkill.....

Hung0702 said:
RE-EDIT: Huh, this is weird. I tried to exit out of app but it froze. Waited a minute and it exited out, but without the expected transition animation. Tried to open it again, but the GPS icon in the notification bar wasn't flashing so I rebooted. Now I don't get any satellites with the same settings as before.
Click to expand...
Click to collapse
Ok, relax, I found that this is not that unusual depending on what ROM / Modem and settings your using. It happend to me with JK2 stock and and stock modem. If your running one of the 2.2 builds update your modem to JL4 or JL1. Also i have found that reseting the GPS data can help after you change modems. Before geting into the unit again, i would recoment clearing your gps data and reverting to STOCK gps setings. MS mode does in some cases make locks look faster, but a weak network connect can cause problems. This is actualy why, i think, that Samsung is using standalone mode as it saves the bird info better. Im not shure about this but for me STOCK GPS SETTINGS WORK!!! Try them before opening up the phone a 2nd time.
As long as you've done the mod correctly and have good contact, you should be in better shape. There is the possablity that you did not bend the contact high enough and it settled back in. DONT OVER BEND but maby just a hair more. Also, dont forget to clean the contacts with a mild solvent as a weak contact will cause oxidation . I use a q-tip and alcohol. Dont use tunner cleaner, i tried this and being non conductinve, i had a problem at for a bit.
Remember, this is also a software issue so dont panic if you do the mod, get good results and then things change. Here is my curent configuration for reference.
Macnut 13
JL4 modem
STOCK GPS SETTINGS
Rom was loaded from a CLEAN Oden version of JFD with eveything formated etc..
Im locking with 8-11 birds out of 13 visable in under 15 seconds with accuracy that under 20ft standing still and 25-35 in a moving car. There are times that things will get a bit worse, but by compairing those times to my Garmin, I beleave this a result of the GPS network or other enviromental issues. I DO have "use wireless networks" as it seams to reduce GPS wander on the JL1 modem , at least in my area. Without it on I get an occational jump but it always finds it way back to good in a very short time. It up to you if you want to use it, its not nessasay, but sometimes helps.
To everyone who might suggest that I'm just one of the lucky one.. When I got this phone, I could not lock on ANYTHING. I could see a few birds, hit some sometimes, get a lock after 5 minutes and lose after the phone went into lock mode etc... you know, all the problems that eveyone else has. Now with the contact mod and updated modems, the results are better than an iPhone and rival my Garmin stand alone GPS.

salvador3 said:
How do I update to JI6? i'm running Macnut 14 rom with the Super_IO kernel.
In the release notes of the Super_IO kernel, it mentions it has the UVJL1 modem. is this more recent than JI6??
Click to expand...
Click to collapse
Your fine, your current config is good, My advice, just update to the JL4 modem.

How do I reset the GPS setting?

Stick Thread!

How do I reset the GPS setting?
Click to expand...
Click to collapse
The most dummy proof way (not that your dumb, I just like simple solutions) is to download this app http://forum.xda-developers.com/showthread.php?t=775154
Click on Secret Codes then Lbstestmode. At the bottom you'll see "gps reset". Just click that!
Or open your dialer and hit *#*#1472365#*#*
Sent from my SGH-T959 using Tapatalk

wow holy crap this fix worked. i live in apartments and after i did this, it locked on to sats for the FIRST time EVER within 30 secs. im amazed this actually worked lol.

so should we assume that any phone manufactured before those dates has these problems?
mine was manufactured before the date, but now that im on 2.2 i usually get a lock on 7 or 8/12 Sats....
but when using google Nav, i get several re-routes and lost signals...
so im not sure if this would help me??

Any hints on how to get the back off after removing the screws? I watched the YouTube video, but I'm not having any luck with my normal sized fingernails.

kboater said:
so should we assume that any phone manufactured before those dates has these problems?
mine was manufactured before the date, but now that im on 2.2 i usually get a lock on 7 or 8/12 Sats....
but when using google Nav, i get several re-routes and lost signals...
so im not sure if this would help me??
Click to expand...
Click to collapse
I got my phone in late July and my GPS performance matches exactly what the OP describes AFTER he did the fix. My phone is pure stock JI6, with no HW mods. So, it doesn't seem valid to assume all pre-October phones have the problem.

Confirmed works... Thanks to all.
- All screen shots were taken from the same indoors location. Phone was sitting in a window.
- There are two before and two after screen shots. They represent the range of results.
- I'm running Macnut R14 with JL4
Before
After

Try this
JD - You might need to go online and order an actual case pry tool. They're usually included in disassembly kits for iPhones etc. Maybe try a guitar pick??
Sent from my SGH-T959 using Tapatalk

kboater said:
so should we assume that any phone manufactured before those dates has these problems?
mine was manufactured before the date, but now that im on 2.2 i usually get a lock on 7 or 8/12 Sats....
but when using google Nav, i get several re-routes and lost signals...
so im not sure if this would help me??
Click to expand...
Click to collapse
No, I would not think so. Something like this is usually a intermittent manufacturing flaw and would not affect everyone or there would be an even larger outrage about it.
Look at it this way. The spring contacts were designed to make contact without too much pressure when the back is properly in place. GOOD engineering would have accounted for slight variations in manufacturing and quality control and would have made the spring contacts overshoot the required distance a little to assure 100% contact in all situations. In this case I think they forgot to account for that and designed them to just touch, invariably some make intermittent contact and some fall just short of good solid contact (there are prior posts about how poor contact can get worse over time due to oxidation and arcing), but at least we have no reports of totally non-working GPS where they would have failed to touch outright. Chances are when October came around one of two things happened.
They decided to fix the issue and reenginerred the design to make better contact
The manufacturer ran out of the old contacts the the new shipment just work better
Either way, although this is a common issue, I don't see the evidence that it affected all pre-October phones.

I'll post screenshots later today. For now I can definitevly confirm that this fix improves gps signal levels and performance.
Sent from my SGH-T959 using XDA App

[BUG FIX] Phantom keypress and screen shot

I've been working on fixing this issue for awhile. Here's the deal:
The problem.
The four keys at the bottom of the phone are monitored by a melfas touchkey chip (http://www.melfas.com/english/touch/sensor.asp) that connects to the main processor via an I2C bus (http://en.wikipedia.org/wiki/i2c). The melfas chip generates an interrupt whenever one of the keys is touched or released. The processor then reads the key value from this chip over the i2c bus. The problem is that the touchkey chip is located right next to the 3G antenna. When the phone is accessing the 3G network the RF energy gets transferred to the interrupt and i2c clock and data lines causing false interrupts to occur. The processor responds to the interrupt by reading the key value from the cypress chip. The symptoms occur more frequently in low signal areas because the phone outputs a higher RF level in those situations which causes more RF interference on the interrupt line.
Most of the time when a false interrupt has occurred the touchkey chip will return a value of zero for the key and the driver will recognize this as a bad key press and ignore it. Sometimes the RF interference on the i2c clock and/or data line causes a valid value to be returned and the driver reports a key press value to the application. In the case where the driver reports a ‘back’ key down, the software sees this as holding the back key down so when you press the power button you get a screen shot. The easiest way to cure this is to always press and release the back key before pushing the power button. This causes the software to see both a key down and key up event which cancels the screenshot mode.
This RFI induced touchkey interrupt happens hundreds of times per second when the phone is using 3G. It produces lots of different symptoms including applications that always seem to shut down. A wide variety of problems can be attributed to this failure. In addition, the processor spends a lot of time servicing these bogus interrupts, which take cpu time away from the other applications. This can make the phone appear to be slow or even freeze up for short periods of time. There’s a good chance that most people have experience this to some degree without realizing the root cause.
Solution one. Fix the driver.
Since this is a true hardware failure, a software solution is going to be less than perfect. After dozens of experiments rewriting the interrupt service routines in the driver I’ve settled on a combination of fixes. The first is to re-test the interrupt input line several times. In normal operation when you touch or release a button, the touchkey chip drives the interrupt line low and keeps it low until the driver reads data over the i2c interface. Since the RF interference is a sine wave and is being sampled it causes the interrupt line to go high and low at a fast rate. Sampling the line multiple times in software increases the chance of finding it in the high state. This is done both in the interrupt handler and then again in the interrupt thread. About 90% of the false interrupts are filtered out by testing the line in the handler. If the interrupt handler doesn’t find the line high after 10 samples, it masks the interrupt so that another falling edge doesn’t produce another interrupt. In testing I’ve noticed that the interrupt handler would run multiple times before the interrupt thread was even called. Once in a while, so many interrupts would get stacked up that the phone would just reboot. It was probably a stack or buffer overflow that wasn’t being handled. Remember, this interrupt would happen many hundreds of times a second. About 90% of the remaining false interrupts are filtered out by sampling this line in the thread. That leaves about 1% of the interrupts that need to be further tested. The second test is to read the data from the chip and discard anything that isn’t a valid key press value. This is easily done with a case statement. Finally, since occasionally a bogus valid value will get through, I set up a timer so that any key down event that doesn’t have a corresponding key up event within 3 seconds is canceled by calling the all_keys_up routine.
This combination all but eliminates the symptoms produced by this failure. The only draw back is that the processor still spends a considerable amount of time servicing the false interrupts. And rarely a phantom keypress does get through. In all, it’s a fairly good piece of duct tape and JB Weld.
During my experiments I used a copy of the kgb kernel. My version with the modified driver is in github at https://github.com/dmriley/kgb. If you want to try this yourself, be sure to use the ‘dev’ branch.
Solution two. Fix the hardware.
There are three signals that connect from the melfas touchkey chip to the processor. They are the two i2c lines: sdc which is the clock and sda which is the data. The third line is the interrupt. In troubleshooting this problem, I took my phone apart and put oscilloscope probes on the three lines. This allowed me to see the real cause of the problem. Since the interference is RFI (or EMI) the only real way to fix the problem is to either remove the RF or make the impedance of the signals much lower. Removing the RF is easy if you don’t need to use 3G. When the phone is using wifi (or no network connectivity at all) the problem does not exist. Also, when you are very close to a cell tower, the phone transmits at a much lower level. This lower level greatly reduces the RFI. Lowering the impedance is a little harder. I2C uses active pull down and passive pull up for the logic levels for both sda and sdc. This means that the impendence is mostly governed by the pull up resistor. This resistor value is typically upwards of 1kohm and probably as high as 3kohms (I didn’t measure it in this phone). Since the impedance only needs to be lowered for the 3G frequencies of around 800MHz, a capacitor can be added from the signal source to signal ground. At 800MHZ a 100 pf cap is about 2 ohms (1/ 2*pi*f*c). That’s a couple of orders of magnitude lower than the pull up resistor alone, and much too low for the RF signal to induce any significant voltage on the line. This value is also low enough not to interfere with the signal rise and fall times for the interrupt line. In the case of the interrupt line, the melfas chip drives the signal low and keeps it low until the interrupt is serviced. Discharging a 100pf cap with a 2mA driver takes only microseconds. This much delay is not noticeable when touching the key and is much less than the amount of time that the processor takes to service the interrupt.
Adding the cap to the interrupt line eliminates false interrupts. A chance does exist that a valid key event during 3G access could cause an incorrect key value to be returned due to RFI on the clock and data lines. The i2c protocol is designed to compensate for capacitive loading on the lines. Although it would cause the clock period to be stretched out significantly it would still only take milliseconds to read the key data from the chip. The difference would be imperceptible. To date I have only added the cap to the interrupt line and have yet to experience an invalid key press.
I’ll post pictures of cap mod.
Summary.
Most people will be satisfied using the software fix. I think that a couple of the kernel devs are incorporating some or most of the driver mods outlined in this document. Both comradesven (kgb dev) and ssewk2x aka Efpophis (glitch dev) were involved in the test and debug process. Much appreciation is given to both of them for the help that they gave me and for allowing me to use and hack up their code on github. Efpophis saved me hours of searching through code. Without their help, I’d still be unable to build a kernel.
UPDATE:30 Mar 2012
The phone had been working fine since the mod. I hadn't seen a screen capture or any of the other symptoms. Then, a couple of nights ago, while I running maps on 3G (a data intensive app) the touchkey backlights started flashing rapidly like the phone was having a little seizure. And then it happened, the voice search popped up. A couple of debug kernels later I've come to the conclusion (and I'm never wrong) that the clock line (SCL) going to the melfas chip was being toggled by the same RF interference that was causing the false interrupts. A random clock along with random data was causing the chip to turn the backlights on and off as well as generate a false interrupt. I was able to reliably duplicate the problem in a couple of really low signal level areas (not hard to find when you live out in the boonies).
I tore the phone apart (again) today and added a 100pf cap to the scl line right next to the chip. I also added another cap in parallel with the 100pf on the interrupt line. I spent about 1/2 hour tonight running 3G data apps in the same location where the problem first appeared. So far, no problems and none of the debug messages have shown up on dmesg.
If anyone wants pics of the added cap I'll open it back up, no problem, otherwise if you look at this photo you can see which pin is scl (although I incorrectly labeled it SDC in the photo). http://forum.xda-developers.com/attachment.php?attachmentid=953824&d=1332117055
If anyone tries these mods I'd be real interested in your results.

Here are some pictures of the cap mod:
this is the open phone showing where the melfas touchkey circuit is:
View attachment 951774

Awesome, thanks for doing this for all of us. Phantom key press is really annoying
Sent from my SCH-I500 using XDA App

the cap. yeah, that's a normal size pen to show scale
View attachment 951812
on the board
View attachment 951821
with notes
View attachment 951820
the antenna problem
View attachment 951822
close up showing touckey circuit. micro sd card for scale
View attachment 951834
my finger
View attachment 951836
back off
View attachment 951838
another view
View attachment 951837
BTW, I took these pictures with my son's fascinate

Wow, we're lucky to have someone as capable as yourself figure out this annoying issue! I've kinda kept up on your work, but seeing this breakdown and the photos is helpful in understanding the root cause of the problem. I do wonder sometimes how Samsung missed this issue in their testing, but at least we have custom kernels that implement your fixes and dramatically reduce the phantom presses!

Uuuhm...You're an awesome human being. Holy crap. -_-
That's some amazing work, thanks!

k_nivesout said:
.... I do wonder sometimes how Samsung missed this issue in their testing, but at least we have custom kernels that implement your fixes and dramatically reduce the phantom presses!
Click to expand...
Click to collapse
Yeah, it's crying shame that Samy couldn't fork over the extra penny to keep this problem from happening in the first place.

sendan said:
Uuuhm...You're an awesome human being. Holy crap. -_-
That's some amazing work, thanks!
Click to expand...
Click to collapse
wasn't just me. had help from other members here. I didn't even know where to start looking when I first started. It's so cool that people are willing to do the level of work that the devs here do without expecting anything back.

electric bill said:
wasn't just me. had help from other members here. I didn't even know where to start looking when I first started. It's so cool that people are willing to do the level of work that the devs here do without expecting anything back.
Click to expand...
Click to collapse
Thanks so much for all the work, and the detail in your post. It is amazing the work everybody does here and the knowledge you pass on to us.
I do have a few questions
Would you mind sharing what kind off iron you used? is that the most bottom line on the board you soldered to? If so, did you have to scratch it or something first? Is it the farthest left line on the chip that was used? Do they make caps that size with leads coming of the 2 sides, and if so would that be a easier mod? Is there a positive and negative side to that capacitor?
I'm really thinking about doing this, if i decide to would you mind sending me 5 of your extra caps for a $10 donation?
Sent from my SCH-I500 using xda premium

Ditto on the $10.00

neh4pres said:
Thanks so much for all the work, and the detail in your post. It is amazing the work everybody does here and the knowledge you pass on to us.
I do have a few questions
Would you mind sharing what kind off iron you used? is that the most bottom line on the board you soldered to? If so, did you have to scratch it or something first? Is it the farthest left line on the chip that was used? Do they make caps that size with leads coming of the 2 sides, and if so would that be a easier mod? Is there a positive and negative side to that capacitor?
I'm really thinking about doing this, if i decide to would you mind sending me 5 of your extra caps for a $10 donation?
Sent from my SCH-I500 using xda premium
Click to expand...
Click to collapse
I did the mod at my workplace under a microscope. I used a metcal (http://www.okinternational.com/product_soldering/mx500) soldering iron but you could use just about any low wattage iron with a really fine tip.
There's four pins on each side of the melfas chip. One end of the cap is soldered right to the interrupt pin which is the closest to the corner. the other end is connected to the ground side of C2 via a solder bridge.
View attachment 953824
I doubt that they make caps that small with leads on them. You could look. It's not hard to make the solder bridge. Remember the scale that were talking about here. That cap is 0.06 inches long by 0.03 inches wide. I wouldn't try to scratch the solder resist from the board because it's a flex circuit on top. Also, the cap is not polarized.
I bought a hundred of these caps for less than $6 including shipping. I'd feel terrible charging someone $10 for five. If you pm me your address I'll stick a couple in an envelope and send them. If you want to give away ten bucks, donate it to a charity like destiny rescue or UMCOR (http://new.gbgm-umc.org/umcor/about/financialinformation/).
Disclaimer:I've been working with parts this size for years and am pretty good at soldering. You risk dorking up your phone if you don't do this correctly. Only attempt if you are skilled at soldering. All information is presented "as is" and without warranty for fitness or use. Your mileage may vary. Void where prohibited, taxed or licensed.

What is the easiest way to implement the band-aid software fix?
I am on CSpire so there are not many proven custom roms out there.

IamUmpire57 said:
What is the easiest way to implement the band-aid software fix?
I am on CSpire so there are not many proven custom roms out there.
Click to expand...
Click to collapse
The fix is in the kernel. I used the KGB kernel as the source for my build. You can download it from github and build your own. If you're running all stock (rom & kernel) you can mod the stock kernel.
I'm really not the expert here on choices. Maybe someone else could chime in.

Too tiny to solder so band-aid?
Excellent research, fix and documentation. I was going to follow the fix, but, when I finally got the phone disassembled, I saw that the bits were much too small for me to solder. And I'm an ex-electronics guy who's worked on surface mount stuff before, so I doubt amateurs will have much luck, either.
So the problem is that RFI is hopping onto the I2C and interrupt lines... Could we just block the RFI? Sure. A grounded piece of aluminum foil which covered the whole Melfus+lines area should do that. So I tried that. Worked great for the soft keys, but, for reasons not apparent to me, my phone would no longer do 3G (stuck in 1X). Perhaps because the big old piece of grounded foil in the middle of the 3G antenna soaked up too much signal?
How about not grounding the Aluminum foil? It wouldn't be tied to ground, so the potential of the Alu foil would wobble, but it might prevent enough RFI from reaching the I2C and interrupt lines.
I opened the phone back up and squished the Alu foil a bit so that it just covered the Melfus chip and the lines heading to the left, and so that it didn't touch what-I-think-is the ground plane right at the upper edge of the PCB. Now, the piece of Alu foil was a rectangle about 6mm wide and 3mm tall. Seems to prevent softkey misfires and my phone seems more responsive. Assuming the results hold, this is a 5 minute fix for the issue and it doesn't require anything more than a tiny screwdriver, a spot of aluminum foil and a moderately steady hand. Wish me luck!

CoffeeDregs said:
Excellent research, fix and documentation. I was going to follow the fix, but, when I finally got the phone disassembled, I saw that the bits were much too small for me to solder. And I'm an ex-electronics guy who's worked on surface mount stuff before, so I doubt amateurs will have much luck, either.
So the problem is that RFI is hopping onto the I2C and interrupt lines... Could we just block the RFI? Sure. A grounded piece of aluminum foil which covered the whole Melfus+lines area should do that. So I tried that. Worked great for the soft keys, but, for reasons not apparent to me, my phone would no longer do 3G (stuck in 1X). Perhaps because the big old piece of grounded foil in the middle of the 3G antenna soaked up too much signal?
How about not grounding the Aluminum foil? It wouldn't be tied to ground, so the potential of the Alu foil would wobble, but it might prevent enough RFI from reaching the I2C and interrupt lines.
I opened the phone back up and squished the Alu foil a bit so that it just covered the Melfus chip and the lines heading to the left, and so that it didn't touch what-I-think-is the ground plane right at the upper edge of the PCB. Now, the piece of Alu foil was a rectangle about 6mm wide and 3mm tall. Seems to prevent softkey misfires and my phone seems more responsive. Assuming the results hold, this is a 5 minute fix for the issue and it doesn't require anything more than a tiny screwdriver, a spot of aluminum foil and a moderately steady hand. Wish me luck!
Click to expand...
Click to collapse
That's great work. I tried that initially with some foil tape over the whole melfas chip without success. This was all documented in the github problem log but it got deleted when the ticket was closed out. In my basement where I was doing my testing, the signal strength is very low so it's a worst case scenario. Maybe the shield will work better if it's shaped just right. I'm not an RF guy so my shield was just a guess. Share some pics with us if you find a solid solution. The shield would be much easier to implement.

electric bill said:
I tried that initially with some foil tape over the whole melfas chip without success.
Click to expand...
Click to collapse
What was not successful about it? You still had phantom keypresses or you lost 3G?
Also, how did you ground the foil? I grounded it against what I thought was a ground plane. And I covered the entire L-shaped assembly (Melfas, lines and all).
[Stating the obvious...:] The idea of covering the Melfas chip and lines with foil assumes that the RFI is getting to the lines from above the chip+lines. The foil wouldn't do anything were the RFI hopping over from elsewhere. But AFAICT the top layer of the PCB is a ground plan and the signal lines head down into buried layers directly from the connector, so I'm not sure how else RFI could get the I2C lines except from in the module...
My un-grounded foil seems to be an improvement, but not a fix, so I might try grounded-foil again and try to figure out why it killed my 3G.
Good to hear that you have a microscope; I still have 20/20 vision as a 40yo, but that's a tiny little area!
I gotta say that I am wildly disappointed in Samsung. If a few electronics-savvy folks polking around the interwebs can find root cause and propose multiple fixes, it's shocking that Samsung won't acknowledge it, much less fix it. I'm due a phone upgrade and I'd love to get an SGS III, but I really don't trust Samsung.

CoffeeDregs said:
What was not successful about it? You still had phantom keypresses or you lost 3G?
Also, how did you ground the foil? I grounded it against what I thought was a ground plane. And I covered the entire L-shaped assembly (Melfas, lines and all).
[Stating the obvious...:] The idea of covering the Melfas chip and lines with foil assumes that the RFI is getting to the lines from above the chip+lines. The foil wouldn't do anything were the RFI hopping over from elsewhere. But AFAICT the top layer of the PCB is a ground plan and the signal lines head down into buried layers directly from the connector, so I'm not sure how else RFI could get the I2C lines except from in the module...
My un-grounded foil seems to be an improvement, but not a fix, so I might try grounded-foil again and try to figure out why it killed my 3G.
Good to hear that you have a microscope; I still have 20/20 vision as a 40yo, but that's a tiny little area!
I gotta say that I am wildly disappointed in Samsung. If a few electronics-savvy folks polking around the interwebs can find root cause and propose multiple fixes, it's shocking that Samsung won't acknowledge it, much less fix it. I'm due a phone upgrade and I'd love to get an SGS III, but I really don't trust Samsung.
Click to expand...
Click to collapse
Yeah, I used what I thought was a ground pad and covered pretty much everything on that little flex board that has the chip on it. It didn't stop the problem. Also, I had a bunch of dmesg stuff in the driver so I could see every time that there was a "missfire" vs just seeing the actual symptoms. A shield could theoretically fix the problem, I'm just not a RF engineer so I went with what I know. With the microscope, it's pretty easy to add the caps. Without, it'd be kinda hard. It probably only took me 20 minutes or so to do the last one I did. The good news it, the cap fix does the trick 100%. We've been running it on three phones without a problem for a few months now.
I totally agree on Samsung's failure. That design defect should have been caught pretty early in development. Maybe these guys have never heard of a Peer Review . It's even sadder if they knew it might be a problem but decided to risk it to save 1/2 cent per phone.
I understand the corporate mentality of denying a problem exists (iphone signal loss is a good example). If they admit it, then they have to fix it and that would be very costly. I'm sure when they started to have a problem they did a cost analysis and decided that losing N number of customers was cheaper than actually fixing all the bad phones.
What made it even worse was trying to find info on the phone design. Samsung was completely unresponsive when I contacted them to get data sheets on the CPU and other info on the phone. It's as if they didn't want me to solve the problem. Come to think of it, they probably didn't want me to. Solving it verifies that the problem exists and isn't just user error.
Anyway, now with my phone fixed and the excellent AOKP ROM and Glitch kernel, I love my fassy.

electric bill said:
Yeah, I used what I thought was a ground pad and covered pretty much everything on that little flex board that has the chip on it. It didn't stop the problem. Also, I had a bunch of dmesg stuff in the driver so I could see every time that there was a "missfire" vs just seeing the actual symptoms. A shield could theoretically fix the problem, I'm just not a RF engineer so I went with what I know. With the microscope, it's pretty easy to add the caps. Without, it'd be kinda hard. It probably only took me 20 minutes or so to do the last one I did. The good news it, the cap fix does the trick 100%. We've been running it on three phones without a problem for a few months now.
I totally agree on Samsung's failure. That design defect should have been caught pretty early in development. Maybe these guys have never heard of a Peer Review . It's even sadder if they knew it might be a problem but decided to risk it to save 1/2 cent per phone.
I understand the corporate mentality of denying a problem exists (iphone signal loss is a good example). If they admit it, then they have to fix it and that would be very costly. I'm sure when they started to have a problem they did a cost analysis and decided that losing N number of customers was cheaper than actually fixing all the bad phones.
What made it even worse was trying to find info on the phone design. Samsung was completely unresponsive when I contacted them to get data sheets on the CPU and other info on the phone. It's as if they didn't want me to solve the problem. Come to think of it, they probably didn't want me to. Solving it verifies that the problem exists and isn't just user error.
Anyway, now with my phone fixed and the excellent AOKP ROM and Glitch kernel, I love my fassy.
Click to expand...
Click to collapse
Yeah: dmesg would be lots better!
My foil status: decent. I'm getting a lot less buzzing, but I still do get **some** in low signal areas (my bedroom). So I'm happier.
Samsung's response: I'm not at all surprised. I used to be an FAE for Cirrus Logic and worked a lot with ARM processors (back in 2000-2003). I got ahold of some of Samsung's datasheets on their ARM processors and was staggered: the datasheet was about 4 pages long and was full of errors, inaccuracies or glossings-over. Our datasheets were 40 pages long and we had 200 page programming manuals available on the web. You got no love from Samsung unless you were looking to buy 5M chips.
Anyways, thanks for you research and help!

I'll be giving that kernel a shot!

Second cap
I finally got around to mod'ing our last phone. Actually, I was finally able to pry it from my teen's hands long enough to do the work. I think she sat home all afternoon and twitched.
Anyway, here's a pic of the two caps. One is on the interrupt line and the other is on the clock (or scl) line. I melted the insulation from a piece of real fine magnet wire to connect between the clock pin and the second cap. The other end of the second cap is just solder bridged to the same ground as the first cap.

[SOLVED] Extremely weak Wi-Fi signal

The Wi-Fi signal on my I9505 is terribly weak. Sitting at the same desk the router is on - full signal; Walk 3-4 meters away - signal drops to 1 line; Go to a different room - disconnects due to no signal. I can only see 3 networks at 1 signal line while on another phone I get 11 networks - all with signal at 2+ lines.
My router is perfectly fine (works as expected and has great coverage on other phones/laptops - it still gives off great signal if I go next door/above/below me).
Phone software side I'd say is fine too, but I'm not 100% sure:
Issue happens both on latest WizCyan (TW based) and on latest RR (CM14 based), both using different kernels.
Currently on XXUHPG1 bootloader and baseband. PDA version is XXUPPI1 (according to the "Phone INFO" app).
Hardware side, I've tried a few things - bent all of the golden springs I could find just a tiny bit upwards, tried to clean the gray contacts on the mid bezel as best as I could (dry microfiber) - they weren't dirty or anything, but they seem scratched/shiny where the spring would have come into contact, is that bad? (I can take pictures if necessary)
I even flipped the blue antenna wire around (though I think that one only affects cell signal).
I also have to note that there's something wrong with my Wi-Fi IC / mobo because sometimes it stops working altogether (won't turn back on), needing a reboot or physical intervention. I doubt that would affect signal strength, as long as it's actually turning on, I guess?
Edit:
SOLVED!
Well, this is probably a very unique/fringe case - I found out there was a crack in my motherboard, just below one of the antenna connectors. I also found out that pushing down on where the crack is relinks the motherboard connections and gives back the full Wi-Fi signal. So I "ghetto-rigged" a piece of plastic to push down on the crack when I put the mid-bezel back in, and it seems to be working for now. Hope it holds up and doesn't cause other issues.

Actually, it could affect signal strength. You might want to check your antenna wire running down the right side of the battery compartment and make sure it isn't broken or partly disconnected.

You should also note that some phones have better antennas, thus having better reception.
So comparing it to a different phone isn't really a good way to measure the effectiveness.

Took some pics, I've no idea if they're of any help. Maybe somebody can tell if there's something wrong.
Strephon Alkhalikoi said:
Actually, it could affect signal strength. You might want to check your antenna wire running down the right side of the battery compartment and make sure it isn't broken or partly disconnected.
Click to expand...
Click to collapse
That's the wire I had flipped around. I even disconnected it to see if there's a difference, and it only weakened the cell signal. Full cell signal when I put it back. No change regarding Wi-Fi. If I run the phone with the mid bezel off, I only get 2 lines even next to the router, and it doesn't even connect - so I suppose the mid bezel antennas connect?
Pwnycorn said:
You should also note that some phones have better antennas, thus having better reception.
So comparing it to a different phone isn't really a good way to measure the effectiveness.
Click to expand...
Click to collapse
True, still, from full signal to 1/0 lines as soon as I go from my desk (and router) to my bed 5m away isn't right. Wi-Fi reception used to be as good on my S4 as on the other phones. (I can't remember exactly when this started.)

I believe you have a radio chip issue. Something that software cannot fix.

Solved. Thank you for trying to help.

@cLick1338: Telling people you solved the issue without revealing the solution doesn't help anyone who may come across this thread in the future. So how did you solve it?

Strephon Alkhalikoi said:
@cLick1338: Telling people you solved the issue without revealing the solution doesn't help anyone who may come across this thread in the future. So how did you solve it?
Click to expand...
Click to collapse
I had edited the first post. Figured it would be most visible for such people.

cLick1338 said:
I had edited the first post. Figured it would be most visible for such people.
Click to expand...
Click to collapse
If you edited it yesterday I wouldn't have noticed it. The XDA app automatically drills down to the first unread post and I don't always think to scroll back up.
Sorry.