[Q] Battery Mainboard Solder - Nexus 4 Q&A, Help & Troubleshooting

So there's lots of questions about bad battery life but haven't found my issue in searches - altho I suspect my issue is a factor for many to some degree.
N4 took a 4' to drop to concrete. Screen cracked. Replaced screen w/no problems. Ran fine for a while on stock 4.4.4. Lollipop comes OTA practically zero day and since the N4 isn't my primary phone I upgrade to play around. Shortly after 5.0, the battery drains and shuts the phone off. I charge it overnight, pull it off, battery is dead, phone shuts down. Will stay on and operate fine on wireless charger but powers down if not connected. Pop off the back again to make sure battery connector is snug and reassemble. Now I've got red light of death. Get Google logo and can boot to recovery options but it just cycles. Disassemble again and ultimately find that the battery pins from the mainboard and their little black housing have come off at some point. Try to solder it back on but there's chips on the back side and there's just no room to get the solder on and pins reconnected. Not w/my skills anyway.
My main question is, has anyone successfully reconnected that annoying mofo? Thinking about skipping the connectors and just soldering wire straight from the battery to the board. I don't see anything in that connector that would be a problem if absent, but any warnings I should know about? Other workarounds?
This is not mission critical, just principle/spite.

Repaired?
gkmocv said:
So there's lots of questions about bad battery life but haven't found my issue in searches - altho I suspect my issue is a factor for many to some degree.
N4 took a 4' to drop to concrete. Screen cracked. Replaced screen w/no problems. Ran fine for a while on stock 4.4.4. Lollipop comes OTA practically zero day and since the N4 isn't my primary phone I upgrade to play around. Shortly after 5.0, the battery drains and shuts the phone off. I charge it overnight, pull it off, battery is dead, phone shuts down. Will stay on and operate fine on wireless charger but powers down if not connected. Pop off the back again to make sure battery connector is snug and reassemble. Now I've got red light of death. Get Google logo and can boot to recovery options but it just cycles. Disassemble again and ultimately find that the battery pins from the mainboard and their little black housing have come off at some point. Try to solder it back on but there's chips on the back side and there's just no room to get the solder on and pins reconnected. Not w/my skills anyway.
My main question is, has anyone successfully reconnected that annoying mofo? Thinking about skipping the connectors and just soldering wire straight from the battery to the board. I don't see anything in that connector that would be a problem if absent, but any warnings I should know about? Other workarounds?
This is not mission critical, just principle/spite.
Click to expand...
Click to collapse
So were you ever able to get the connector solder back on? I think mine break because it was to hot when I was removing the battery. My nexus 4 shutdown on me, my battery was expanded. I was wondering why my screen was being pushed out. I wonder if Android 5.0.1 is causing phone to run to hot. Never did this with Android 4.4.4. Hope the connector can be fixed. Maybe I take it to a solder shop.

jameswhite4684 said:
So were you ever able to get the connector solder back on? I think mine break because it was to hot when I was removing the battery. My nexus 4 shutdown on me, my battery was expanded. I was wondering why my screen was being pushed out. I wonder if Android 5.0.1 is causing phone to run to hot. Never did this with Android 4.4.4. Hope the connector can be fixed. Maybe I take it to a solder shop.
Click to expand...
Click to collapse
Not yet. I pulled the connector back off and cleaned everything up. I found that even very small gauge solder is too sloppy for the 4 small connections. Not to mention there's chips on the back side so you can't linger too long with heat. So my plan is to try again with some conductive ink and/or gel. If that doesn't work I'm just going to use wires to bridge the battery right to the board. Haven't had time to work on it but I'll follow up here when I do.
Did you get a replacement battery? Lithium batteries can swell because of overcharging. There are definitely more than a few N4 owners who had the same issue. A replacement battery won't solve that problem but it could be more tolerant of it, for a while - and depending on if it was "user error" or a fault in the phone's overcharging protection circuitry. Don't go to the trouble of having someone solder the connector back on with the old battery.

Related

Water damage

Hi. My phone got wet in my jacket pocket while riding my motorbike. It was probably wet for an hour or so before I got home and started attending to it. Obviously as it was in my pocket it didn't get submerged or anything, but i still found water residue inside. I took it apart, submerged the motherboard in isopropyl alcohol for a couple of hours and then left it to dry. Today it is booting up however I have noticed a couple of problems.
The phone will not start up unless it is connected to a power source when I try to start it. It will stay on if i unplug it.
It won't charge. First time I booted it it said 41%. As soon as I restarted it had dropped to 17% and is now falling even when plugged in. It does claim to be charging when connected however.
The front camera looks like one of those face-morphing apps (Is there's water around the lens or something?).
It also feels quite hot around the top of the phone when it isn't doing anything.
The loud speaker is not working (fine, I'm guessing that's just a case of swapping it out).
Could the first two just be the battery or some sort of issue with the USB interface? Any ideas how to fix these issues? Thanks!
Clean your usb port. I sometimes clean it with 99% alcohol and a toothbrush when I got some moister damage.
When you charge it, check battery stats and see if it says that it's usb connected.
If so, then you might need to flash a custom kernel (I used Ktoonz for it) and raise the charging stream true usb.
Because your usb port got wet, it thinks you are charging true usb. When charging true usb it will charge way slower. It's als probably the cause for your phone getting hot for no reason.
Lennyz1988 said:
Clean your usb port. I sometimes clean it with 99% alcohol and a toothbrush when I got some moister damage.
When you charge it, check battery stats and see if it says that it's usb connected.
If so, then you might need to flash a custom kernel (I used Ktoonz for it) and raise the charging stream true usb.
Because your usb port got wet, it thinks you are charging true usb. When charging true usb it will charge way slower. It's als probably the cause for your phone getting hot for no reason.
Click to expand...
Click to collapse
I will try that now! Any idea why it won't start unless connected? I've just not a new battery, no change on that issue.
EDIT: It's now starting fine. I'm waiting for a replacement USB connector to hopefully fix the charging issues. It's still getting hot when it's just sitting on the table and the battery is draining at light speed.
icedragon999 said:
I will try that now! Any idea why it won't start unless connected? I've just not a new battery, no change on that issue.
EDIT: It's now starting fine. I'm waiting for a replacement USB connector to hopefully fix the charging issues. It's still getting hot when it's just sitting on the table and the battery is draining at light speed.
Click to expand...
Click to collapse
Good to hear it's booting again. From my experience these issues are temporarily and will disappear over time. The kernel and changing the charging speed fixed the same issues for me. I'm now running my normal kernel without any tweaks. So you might try it before swapping the connector. But that's up to you.
Lennyz1988 said:
Good to hear it's booting again. From my experience these issues are temporarily and will disappear over time. The kernel and changing the charging speed fixed the same issues for me. I'm now running my normal kernel without any tweaks. So you might try it before swapping the connector. But that's up to you.
Click to expand...
Click to collapse
I had already ordered the bits and they were only cheap so went ahead and swapped them out. New USB connector flex and new speaker. Frustratingly I still have no sound. It's charging fine but the battery is still dropping off a cliff (like half an hour from fully charged) and it's still getting hot. I even gave the motherboard and connectors a good clean with high purity alcohol and some cotton swabs. Could the board have suffered permanent damage potentially?
Strangely, none of the water indicator stickers have triggered and it's still in warranty so if worst comes to worst I guess I can go down that avenue.

Treoubleshooting dead Nexus 7 (2012) 3G after screen replacement

I had my N7 screen broken and the bezel damaged and i have had it lying around for about a year now. I finally replaced the screen and bezel on my tablet but it won't turn on any more. Looking for some info on how to troubleshoot what's the issue. What I've done so far is:
Checked that the battery seems to be fine and charged. Using a multi-meter on the battery connector gives a 4.15 V reading. The connector is properly connected (I get the same 4.15 V on the places where the battery connector socket meets the motherboard).
Changed the ribbon cable after finding out that the battery seems to not be at fault. This had no effect.
Tried to put back the old broken screen and bezel to see if maybe the new ones are damaged. Last time i used the tablet with the still broken screen it was able to power on and boot. Now after the fix using the old screen and bezel didn't work.
I have tried to hold the power button with or without holding the volume down button for various amounts of time with no effect.
As i see it now there are a couple of equally plausible things that could have gone wrong.
I have both damaged the new and old ribbon cable while changing the screens.
There is still something wrong with the power circuitry despite battery being at healthy 4.15 V.
The new bezel and screen that came from e-bay were damaged on arrival.
I have damaged something else while changing the screen.
Any ideas on how to troubleshoot any of this?
rihardsk said:
Checked that the battery seems to be fine and charged. Using a multi-meter on the battery connector gives a 4.15 V reading. The connector is properly connected (I get the same 4.15 V on the places where the battery connector socket meets the motherboard).
Click to expand...
Click to collapse
Now some 24h later i'm getting 3.8 V. Which according to this http://forum.xda-developers.com/showthread.php?t=2195070 corresponds to battery being at about 60%. Could it be that the tablet is powering on but the screen stays off due to a damaged LCD ribbon cable? Is N7 in general able to boot up with a damaged LCD ribbon cable?

p602 screen blinking on lower charge

im on lineage os and after around %30 screen starts to blink and if it blinks much it reboot does anyone know a fix to this its really annoying
Re-seat and probably clean the contacts of the cables running across the battery on the backside. Only the battery connector is known to develop bad solder connections, but here probably just the two display cables are affected and somewhat loose, or just the one for the backlight.
Kenan07 said:
im on lineage os and after around %30 screen starts to blink and if it blinks much it reboot does anyone know a fix to this its really annoying
Click to expand...
Click to collapse
Battery. This is a common issue on samsung devices, you need to replace your battery.
The removal and reattachment of the second ribbon cable(the first is for usb) may actually fix the screen during a battery replacement.
I changed my battery from 2013 just a few weeks ago. Remaining capacity must've been around 50-60 percent. And it was bulging and rear plate and the touchscreen were bending iutward, too.
But no display issues.
Not even the corona (not the flu) effect some guy in the forum recently experienced, which may have been caused by pressure from the battery. And the sudden disapperance of this effect may have meant that there was a gas exhaust from the battery's two cells, flattening them...

Battery Drain

I have a VS995 and this replacement battery. I'm getting less than 2 hours of SOT with both Lineage 18.1 offical and the new project lighthouse ROM at less than 50% brightness. I have greenify and ACC installed with magisk as well as no gapps. Any idea how to fix the drain?
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Hello ROMSG,
Can you confirm the battery is drained vs being read as drained? You could try measuring the voltage on battery contacts before and after to confirm.
Or, since this would not hurt, without even confirming, for fun, try and clean out your USB port and the C end of the USB cable with strong alcohol, and then compressed air. Dry for sure - leave it in the sun for a while laying on or right next to some table salt.
Why:
I just finished analyzing a thread with unrelated issue, but there, it seems to me that bad USB port was causing get this: low reading from otherwise good battery (or actually create a drain - dark current on the USB connector itself). No idea why, but must be connected somehow.
I had re-soldered USB port twice in the past and once the power switch on my own devices, so it would not surprise me at all that those internal components would fail. And I am kind of super precise in how insert the cable, just time, I guess.
Funny how things work. Today I received a phone I bought from eBay for $50, because it was "Google FRP Locked". Mint black H918, no water damage. I thought I'd use the LGUP to re-load the software and may-be make it work, or something, you know, for practice learning about this stuff.
Well, it would not boot past the T-Mobile screen. Finally I made it boot to Factory Reset screen, pressed YES and it went black. No more boot, as it reported the battery (which was about 70% full before this) is now at 0%.
From 70% to 0% in a few unsuccessful boot attempts? Wow, that's really something. It did not get hot.. So, where all that energy went? I mean how did it dissipate 11.9 x 0.7 = 8.33 Wh ? It took about 15 minutes if that, so it was dissipating at 4 x 8.33 = 33.32 Wh speed without even getting hot? That's insane.
Anyway, the USB connector looks horrid, and the charge percentage is going ON and OFF when in the USB cable is in it. The USB cable feels loose in the port.
I tried cleaning but it is too far gone. I am going to replace the USB connector with a new one.
But do you see, again, the same link between discharging the battery / bad USB port and boot-loops? If true, this means that there might be a sea of perfectly good phones on eBay, just with bad USB connectors, boot-looping and eating batteries. Re-solder the USB port and you're good to go!
I would be excited to find out what was your result.
Descent2 said:
Funny how things work. Today I received a phone I bought from eBay for $50, because it was "Google FRP Locked". Mint black H918, no water damage. I thought I'd use the LGUP to re-load the software and may-be make it work, or something, you know, for practice learning about this stuff.
Well, it would not boot past the T-Mobile screen. Finally I made it boot to Factory Reset screen, pressed YES and it went black. No more boot, as it reported the battery (which was about 70% full before this) is now at 0%.
From 70% to 0% in a few unsuccessful boot attempts? Wow, that's really something. It did not get hot.. So, where all that energy went? I mean how did it dissipate 11.9 x 0.7 = 8.33 Wh ? It took about 15 minutes if that, so it was dissipating at 4 x 8.33 = 33.32 Wh speed without even getting hot? That's insane.
Anyway, the USB connector looks horrid, and the charge percentage is going ON and OFF when in the USB cable is in it. The USB cable feels loose in the port.
I tried cleaning but it is too far gone. I am going to replace the USB connector with a new one.
But do you see, again, the same link between discharging the battery / bad USB port and boot-loops? If true, this means that there might be a sea of perfectly good phones on eBay, just with bad USB connectors, boot-looping and eating batteries. Re-solder the USB port and you're good to go!
I would be excited to find out what was your result.
Click to expand...
Click to collapse
Lg up typically causes battery drain but not like what you described. Also reflashing wont fix frp in all cases, since the versions of android on these devices is so old frp bypasses are typically a better route. I know from expierence.
LGUP does that? How weird, why? This one is also a bug, most likely.
Thank you for the tips! I had no idea. I just wanted to try different things and see what works. Typically, I'd drop my phone like in a carwash and crack the screen. So, now that I am a little smarter, I try to buy many hardware backup pieces before I need them. So this is essentially an extra screen. But since it works, why not brick it, right? Learn something along the way.
Nevertheless, I need all the hints I can get. Not a pro here by any means. Do you know of any FRP bypass method you thin works good on H918?
Since you're not new to this, would you mind if I start a conversation with you? I need answers to a couple of questions that seem to be omitted everywhere or I can't find where they are discussed.
Also can't wait to find out if you have found the USB port to be the cause of your power drain or if you found it not to be related.
Descent2 said:
LGUP does that? How weird, why? This one is also a bug, most likely.
Thank you for the tips! I had no idea. I just wanted to try different things and see what works. Typically, I'd drop my phone like in a carwash and crack the screen. So, now that I am a little smarter, I try to buy many hardware backup pieces before I need them. So this is essentially an extra screen. But since it works, why not brick it, right? Learn something along the way.
Nevertheless, I need all the hints I can get. Not a pro here by any means. Do you know of any FRP bypass method you thin works good on H918?
Since you're not new to this, would you mind if I start a conversation with you? I need answers to a couple of questions that seem to be omitted everywhere or I can't find where they are discussed.
Also can't wait to find out if you have found the USB port to be the cause of your power drain or if you found it not to be related.
Click to expand...
Click to collapse
What version of android is your h918 on? I'm happy to answer any questions you have.
Hi Guys,
Mine was F800L, and it seems like it have the same problem, bad connector. Even though I unplug the battery, when I plug the charger, it's drain 0.3-0.7 Amps, and it's get hot without turning on.
I am a little scary to desolder the usb port.
Yes xdanubi, replacing the USB port is a tricky deal. I have replaced few USB ports before, and this time I had only two jobs: replace a power switch on one phone and the USB port on H918. I did the power switch soldering job without issues, and I ruined the H918 in my attempt to replace the USB port.
What went wrong:
-My work setup was too low magnification for the H918 job. I should have upgraded to a higher magnification first, but instead I pushed ahead hoping that my sharp eyesight will haul me out as usual.
-I used ChipQuick Low Melt solder paste to mix in with the original solder in order to drop the temperature when removing the port. This was a mistake. The paste produced several independently moving micro solder balls and they run around uninhibited and I did not notice that until too late when I was examining the empty board using high magnification hand held loupe after removing the port. I should have used a Low Temp solder in a metallic form at this stage. That would not create the solder balls. Why didn't I use the metallic low temp solder? I had it at hand! Because the magnification was too low for this job and I did not feel comfortable enough to precisely apply the metallic form. Applying the paste from a syringe is easier when the work area observation is limited.
-I have not washed the board in alcohol prior to starting the job. What this did is even though I have applied the MG Pink Peelable Solder Mask jelly to the area next to repair zone to seal and protect all of the surrounding components, the flux from the solder paste still lifted the peelable mask and allowed the metal balls to run under it to get stuck to some of the smallest components. I should have thoroughly wash/brush the repair area with 97% alcohol and dry before applying the Peelable Solder Mask to have it adhere better.
All in all, I was too confident I can do it because I have done that several times in the past. Things got a lot smaller since then. This USB port on V20 is surrounded by a number of smallest components I have ever seen in SMD, and one needs to have his tools and procedures just right to get thru this. My second H918 is now what i purchased it for - just a bunch of parts.
This doesn't mean you should not try to get it done. Just be aware of particular difficulties, and get your tools, and understand every step of your procedure as you design it and know exactly why you are taking it. Also, some people always seem to get it done just on pure luck, you may just be one of them. I think if you heed my warnings and account for what I did wrong, watch few good videos and practice a little on some dead boards, you'll be all right.
Here are my measurements of power consumption from a working H918 for a comparison:
Battery removed.
Phone is connected to USB charger
Mini screen has a light gray backlight and is clearly separate from the main screen which remains black.
A battery symbol with flashing red question mark is displayed on the main screen
Phone OFF and does not start when I use the power button.
Temperature does nor rise, phone stays cold.
Current: 0.25 - 0.27 A
79% Battery is installed and charged to 85%
Phone is connected to USB charger
Both screens are black.
A battery symbol is displayed on main screen with percentage of charge and green fill.
Phone OFF but will start when I use the power button.
Temperature does nor rise, phone stays cold.
Current: 0.48 -> -> 0.37 A
85% Battery is installed and continuously charged
Phone is connected to USB charger
Both screens are black (power button press is needed to display battery charging percentage)
Phone is OFF
Temperature on power button is 30 C
Phone was OFF but is now started using the power button. Booting.
Both screens are ON
Temperature on power button is 32 C
Current: 0.60 A
Phone is ON and is in Airplane mode.
Both screen are ON
Temperature on power button is 31 C
Current: 0.47 A (Battery is now at 89%)
Hope this helps
I think your current measurements are OK. But your temperature is not OK. Try to see where the heat is coming from? IS it coming from, the CPU (felt on power button) or the USB port? In your case it would not be the battery since it is removed. It should not be the CPU either since the phone hasn't been started. I am not all that clear still on what exactly in the USB area creates the heat. It would be awesome if you could produce an InfraRed picture of the phone with the back cover off while being hot while still OFF without battery and on charger. If you have an access to the IR camera like FLIR. It may not necessarily be the port itself or it's connections. It could be one of those small SMD components next to the port that gone bad, and if that is true, replacing only the port won't help.
Descent2 said:
Here are my measurements of power consumption from a working H918 for a comparison:
Battery removed.
Phone is connected to USB charger
Mini screen has a light gray backlight and is clearly separate from the main screen which remains black.
A battery symbol with flashing red question mark is displayed on the main screen
Phone OFF and does not start when I use the power button.
Temperature does nor rise, phone stays cold.
Current: 0.25 - 0.27 A
79% Battery is installed and charged to 85%
Phone is connected to USB charger
Both screens are black.
A battery symbol is displayed on main screen with percentage of charge and green fill.
Phone OFF but will start when I use the power button.
Temperature does nor rise, phone stays cold.
Current: 0.48 -> -> 0.37 A
85% Battery is installed and continuously charged
Phone is connected to USB charger
Both screens are black (power button press is needed to display battery charging percentage)
Phone is OFF
Temperature on power button is 30 C
Phone was OFF but is now started using the power button. Booting.
Both screens are ON
Temperature on power button is 32 C
Current: 0.60 A
Phone is ON and is in Airplane mode.
Both screen are ON
Temperature on power button is 31 C
Current: 0.47 A (Battery is now at 89%)
Hope this helps
Click to expand...
Click to collapse
Thanks for the reference. Clearly, mine has hardware problems, because even after doing factory reset, the problems persist. Tried to flash the stock pie kdz, still the same result. Without battery, the current drraw arround 0.6A, with battery plugged the phone off around 1.3A, and with phone on can be as high as 1,9A.
One thing that I am still doubt about the problem though, that the usb port still functioning, both for charging and data transfer. But the strange part, when the phone is off, whenever I plugged the usb, the phone boot up, both on PC usb or charger only.
The other strange part was that when the phone got realy hot (I measure 54 with IR gun, and around 60 reading the /sys/class/thermal/thermal_zonexx/temp file, the lower part around usb port keep cool, it is the upper part that get hot.
Descent2 said:
Yes xdanubi, replacing the USB port is a tricky deal. I have replaced few USB ports before, and this time I had only two jobs: replace a power switch on one phone and the USB port on H918. I did the power switch soldering job without issues, and I ruined the H918 in my attempt to replace the USB port.
What went wrong:
-My work setup was too low magnification for the H918 job. I should have upgraded to a higher magnification first, but instead I pushed ahead hoping that my sharp eyesight will haul me out as usual.
-I used ChipQuick Low Melt solder paste to mix in with the original solder in order to drop the temperature when removing the port. This was a mistake. The paste produced several independently moving micro solder balls and they run around uninhibited and I did not notice that until too late when I was examining the empty board using high magnification hand held loupe after removing the port. I should have used a Low Temp solder in a metallic form at this stage. That would not create the solder balls. Why didn't I use the metallic low temp solder? I had it at hand! Because the magnification was too low for this job and I did not feel comfortable enough to precisely apply the metallic form. Applying the paste from a syringe is easier when the work area observation is limited.
-I have not washed the board in alcohol prior to starting the job. What this did is even though I have applied the MG Pink Peelable Solder Mask jelly to the area next to repair zone to seal and protect all of the surrounding components, the flux from the solder paste still lifted the peelable mask and allowed the metal balls to run under it to get stuck to some of the smallest components. I should have thoroughly wash/brush the repair area with 97% alcohol and dry before applying the Peelable Solder Mask to have it adhere better.
All in all, I was too confident I can do it because I have done that several times in the past. Things got a lot smaller since then. This USB port on V20 is surrounded by a number of smallest components I have ever seen in SMD, and one needs to have his tools and procedures just right to get thru this. My second H918 is now what i purchased it for - just a bunch of parts.
This doesn't mean you should not try to get it done. Just be aware of particular difficulties, and get your tools, and understand every step of your procedure as you design it and know exactly why you are taking it. Also, some people always seem to get it done just on pure luck, you may just be one of them. I think if you heed my warnings and account for what I did wrong, watch few good videos and practice a little on some dead boards, you'll be all right.
Click to expand...
Click to collapse
I have a bad eyesight and only have a cheap magnifying glass, so maybe not now. Might as well buy another v20, because the cheapest trinocular still more expensive than that phone.
Descent2 said:
I think your current measurements are OK. But your temperature is not OK. Try to see where the heat is coming from? IS it coming from, the CPU (felt on power button) or the USB port? In your case it would not be the battery since it is removed. It should not be the CPU either since the phone hasn't been started. I am not all that clear still on what exactly in the USB area creates the heat. It would be awesome if you could produce an InfraRed picture of the phone with the back cover off while being hot while still OFF without battery and on charger. If you have an access to the IR camera like FLIR. It may not necessarily be the port itself or it's connections. It could be one of those small SMD components next to the port that gone bad, and if that is true, replacing only the port won't help.
Click to expand...
Click to collapse
Sadly though, I don't have access to any IR cam. I do indeed try cheaper method "ouweee" test like Rossmann did, first using bare finger, then using a some drop of IPA and see where the particular component that dried up first.
As far as I can tell, the below area near charging port were fine. nothing dried up fast in the small component area near simcard, and the small component area under the fingerprint sensor. The one that heated up fast was the most left area covered with shield.
So I don't know weather it's still usb port problems or other hardware problem.
On V20, the CPU is just like on PC, is attached to the board, but touching a metal heatsink (which is the internal frame) with a healp from some pink glob of crappy looking thermo paste. Actually, the CPU itself is covered tightly with a memory chip soldered right on top of the CPU, and the roof of that is sticky-glued to a copper foil, and then that copper foil is covered with the paste glob and that is stuck to the frame.
Few points to note right here:
- the reason that V20 has thermal issues, I think, is due to poor thermal design: three interfaces (CPU --> memory chip --> copper foil --> metal frame heatsink), and each has some less than 100% efficiency in thermal energy conductivity. There might even be a fourth interface if the CPU has a lid, like that on PC, but unlikely so, most probably it's an exposed one like on the graphics cards.
- each of these thermal interfaces has it's own expiration date. At this point in time, you don't know how many of them are expired.
- hardware guys already are doubtful about the goofy looking "thermal solution" paste that is applied between copper film and the frame. How efficient was it to begin with?
- if you had removed the board before, or if you had dropped the phone when this paste was already dried up, it is very likely that it has de-touched from the frame and there is an air gap. Typically this is not how a phone is designed and this is a surprise to some folks.
What ideally needs to be done is the memory chip needs to be removed, the interface conduction layer renewed, and chip needs to be soldered back. Then the renewal needs to be carried out with respect to the second and third interface as well.
Without having to solder anything, you can relatively easily replace / thinker with the second and especially the third interface. The second will require the copper foil to be peeled off. On the phone I ruined, I threw that foil away, intending to go directly from memory chip roof to the frame, but alas, I didn't get to try that. I think that the high efficiency thermal conductive solutions such as liquid metal or diamond pastes are not good here, because there is the reason the LG used the glob of chewing gum it seems - because the interface between the roof of the memory chip and the frame lacks the close tolerance required for a high efficiency conduit to work. Plus the phone has some flex to it, so even if yours happen to be aligned extremely tightly, this would keep changing. For this reason, I think the thermal conduit needs to be a high volume / flexible one, like that again, on the graphics cards. This could be a thick paste or a sticky pad.
The reason they used the copper foil and not a direct connection between the chip and the frame, I think was because the interface between the roof of the memory chip and the copper foil is more precise and is much more flex stable, so, by using a higher efficiency / thinner conduit there they were aiming to help the total efficiency at least a little bit.
I wanted to clean the roof of the memory chip and use some good video card thermal paste / goo / glue / pad directly connecting it to the frame during re-assembly.
I think this is what you can try to do as well. You can leave the copper foil there for now, and try just the third interface. If your results are not significant, then try and remove the foil as well. None of this will require soldering or a high magnification equipment. Just some patience, alcohol, a steady hand and at least a PC experience with the same.
Be careful with the screws. The screws are all different length, and when I opened mine I was following a guidance that there are two groups, but found it to be wrong as my phone seemed to have at least four groups of different screws. It was too late, however, because mine were already mixed within two groups I created. So, I would advise to create a diagram of screw location and keeping track of which screw goes where. I think that many times this phone is taken apart and put together, without this tracking, some screws end up too long for where they were placed and holding parts loosely, thus adding to the flex that might be cracking the older brittle thermal interface.
Frame Thermal Interface Touch Point:
Peeling Off the Copper Foil:
Copper Foil is Removed - Roof of the Memory Exposed :
xdanubi said:
Might as well buy another v20, because the cheapest trinocular still more expensive than that phone.
Click to expand...
Click to collapse
Absolutely. The 20x binocular from AmScope on ebay is around $190. Since Iam only an amateur, I am considering building a DIY usb webcam based microscope like the one EEV blog had reviewed or better. Reading about optics now, - I am an absolute newbie to optics design.
Amazon has this phone "new" for $70 with varying reviews. Might just try that, since on e-bay or Swappa you'd likely get a phone someone from XDA already "worked with" for a while.
I too am baffled with why some phones do turn on spontaneously when charger is connected. From my experience with PCs, this usually indicates:
-- bad BIOS battery
(is there a BIOS battery cell on a phone? Yes, I know there was one on Galaxy, maybe there is one on V20 as well?) This would not generate any heat though.
-- bad corrupted BIOS
(we are on XDA, lol. Should we really try throwing this stone?) But really, maybe a full reflashing should help? I mean a complete, like a full KDZ, not just wiping of data partition which is what a factory reset really is. BUT YOU ALREADY TRIED THIS
-- some dried out capacitors around power on circuits (this one can create heat)
Again, FLIR is needed for this. Or careful thermal probing of SMD components with board being fully connected while outside of the case and plastic housing. Once a hot one is found this could be examined further.
Some research directions here...
xdanubi said:
The one that heated up fast was the most left area covered with shield.
Click to expand...
Click to collapse
Could you show which area was heating up:
xdanubi said:
Without battery, the current draw is around 0.6A, with battery plugged the phone off around 1.3A, and with phone on can be as high as 1,9A.
Click to expand...
Click to collapse
You clearly have about 0.3 A to 0.6 A dark current. Something is consuming this energy and dissipating it into heat. When capacitors are shot they now represent a short on the circuit where there not supposed to be one. Such short will now create this dark current.
Capacitors fail due to old age, high heat (vicious circle), and bad power supplies that deliver spikes and poorly filtered power. Big electrolytic capacitors dry out, explode, leak, but SMD capacitors fail too - they crack and melt.
Code:
https://www.youtube.com/watch?v=IciwMsWX_Y4
There could be other failed components, it's just that capacitors are ubiquitous in this regard.
Descent2 said:
- if you had removed the board before, or if you had dropped the phone when this paste was already dried up, it is very likely that it has de-touched from the frame and there is an air gap. Typically this is not how a phone is designed and this is a surprise to some folks.
Click to expand...
Click to collapse
I do remove the board, to see if there's any clear evidence of burned/short capacitors. And indeed I do have the urge to remove that pinky gummy blob, and ad some PC's cpu paste to it. But the fact that I still feel a good heat to the screen area directly below it, it means that it's still have some good heat conductivity, so I'll leave that to deal with it later.
Descent2 said:
What ideally needs to be done is the memory chip needs to be removed, the interface conduction layer renewed, and chip needs to be soldered back. Then the renewal needs to be carried out with respect to the second and third interface as well.
Click to expand...
Click to collapse
that's one hell of BGA rework.
Descent2 said:
I think this is what you can try to do as well. You can leave the copper foil there for now, and try just the third interface. If your results are not significant, then try and remove the foil as well. None of this will require soldering or a high magnification equipment. Just some patience, alcohol, a steady hand and at least a PC experience with the same.
Click to expand...
Click to collapse
Thank you, I'll do it later after clearing some other problems.

Is the vibration motor supposed to be soldered to the motherboard?

Hi,
Please can anyone tell me whether the little connector on the vibration motor is supposed to be soldered to the motherboard or does it just touch at a certain place?
I've already posted another thread about having replaced the battery but it doesn't seem to charge.
Without going into details all over again, a local repair shop replaced the charging port last week - my phone was returned in seemingly working order but they had assured me a bulging battery was OK. I charged my phone but the battery was draining quickly, which was what led me to research a bit more and discovered how dangerous it can be so I ordered a new one.
In the process of fitting the new battery, I discovered half the screws in my phone missing, no copper tape, plus there is no black rubber cover over the charging port & vibration motor as is shown on the guide for replacing the battery on the fixit.com website.
So I'm wondering if the small square 'connecctor' (?) part of the vibration motor ought to be soldered to the motherboard or is it just normally held in place by the black rubber cover? In my phone now, the 'connector' doesn't stay touching motherboard so I'm not sure if this would affect the phone and stop it from functioning or would it just mean the vibration wouldn't work?
Would this affect whether the battery could charge or not?
(Incidentally, I discovered that the the battery connector was upside down compared to the pictures in the ifixit.com guide (the red wire was nearest to the battery instead of the black wire being nearest) so I was hopeful that by correcting it to match the picture, I would have solved the problem but unfortunately, it didn't make any difference. When I connect a wall charger, the screen just flashes and when I connect it to my laptop, it just gets a blinking white led but nothing more. It seems strange to me that it wouldn't make a difference - is it like a usb-c cable in that it can go either way round?)
The battery seller asked for photos of the new battery in my phone and has now offered to replace it - is this likely to make a difference or is the vibration motor not being attached to the motherboard the cause of the problem?
I'll be so grateful for some help.

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