Android PX5 headunit - black screen but touch works - Android Head-Units

Hi
I got a PX5 headunit that suddenly had black screen. No update done on it.
Everything else works, touch function too.
I bought another "used" and smaller model and replaced the PX5 chip, then the screen goes black too, everything else works just like the other.
Is there any screen disable function or something that can have been pressed or something as for me it seems either that or the chip that is blown?
I'd appreciate any help, thanks a lot

Maybe only the screen is without backlight. Take a bright light and check if you see something at the black display, if it showing something.
I realised when the back light is turned off, there is still something visible at the display, when a bright light lights on it.

Unfortunately I tried replacing the screen from the other unit.. Still black. Nothing on the screen but touch work.
It is like the monitor is disabled.

BimmerChriz said:
Unfortunately I tried replacing the screen from the other unit.. Still black. Nothing on the screen but touch work.
It is like the monitor is disabled.
Click to expand...
Click to collapse
Have you checked the ribbon cables . I had this issue also wound up being the ribbon cable wore warn not making proper contact all i did was sled the cable back to make contact on the different part of the ribbon cable
Sent from my SM-G965U using Tapatalk

Yes I have replaced the ribbon cables too from the other unit.
Replaced everything..
But when I replace the PX chip to the other unit, it is the same. Everything works but black screen.
That is why I think either a software function or the chip is malfunctioning?

BimmerChriz said:
Yes I have replaced the ribbon cables too from the other unit.
Replaced everything..
But when I replace the PX chip to the other unit, it is the same. Everything works but black screen.
That is why I think either a software function or the chip is malfunctioning?
Click to expand...
Click to collapse
Thought i read somewhere when you replace the px5 chip it loaded with android on it or it meant with px5 chip with board
Sent from my SM-G965U using Tapatalk

Old thread but if anyone facing the same #it, I have been looking for why that happened for over 2 months, and finally I decided to re-solder all the pin headers on the PX5 chip board (board not the chip itself just the black 2 rows pin headers), then with some pressure connecting the pins back to the board and BOOM screen is working again like new !
Things I tried and it failed
- I tried measuring backlight voltage = 5v
- I tried tracing the screen board for any bad diodes or transistors or filters, all were working
- I tried disassembling the screen and replacing the backlight LED
- I tried taking the screen backlight to another working screen for test and it lit up
- I tried restarting, hard reset, everything - nothing.
Hope this helps someone later.

Related

[Q] Backlight only when turning HD2 on, no picture

So this was my first breakdown of a phone...my brother gave me an HD2 with a non-responsive digitizer, everything else seemed to work just fine.
I disassembled it, accidently tearing the flex cable after it gets thin and goes to the volume buttons. Anyway...I replaced the digitizer...thinking I could just modify the volume via software controls, and stupid me had previously set the hd2 to boot into magicdlr always when the phone turned on. So when I turned on the phone I couldn't do anything because it would boot into magicdlr and I had no volume buttons to scroll up and down, and the option selected was boot into windows which was not on the phone (only cm7 was at this time).
Anyway...after getting a replacement flex cable, and reassembling everything, I couldn't get the lcd to work. Backlight would light up, but no picture, no sound, just a vibrate and the backlight turning on. I tore it down, triple checked all the connections, and still the same thing
So I tried a seperate lcd assembly, tripled checked all connections, and still same issue as the above paragraph, backlight but nothing else when I try to power on. I also retried the old flex cable (the one without the volume connector) and that didn't make a difference either.
My only guess is that I messed up the lcd connector on the mainboard, even though it doesn't look visibly damaged in anyway. Does anybody have any other ideas/suggestions?? I would love to get this up and running as its been my first smartphone project...I've done lots of works on desktops and laptops but never smartphones.
gdawson6 said:
My only guess is that I messed up the lcd connector on the mainboard, even though it doesn't look visibly damaged in anyway.
Click to expand...
Click to collapse
This is my suspicion too!Even not visible at first sight, try again with a magnifier!
Good luck!

HTC HD2 assembly problem

Hi guys,
I just disassembled my HD2 to replace my broken digitizer and touchscreen.
But now i'm stuck with a problem.
What shall I use to glue both items together again?
And the keyboard makes some issues.
I tried to place both parts over eachother to see if they fit but I can't press the keys after it.
Seems like they are stuck.
That's why I didn't want to use superglue because after assembling it I wouldn't be able to change anything.
Maybe pictures tell more than words.
http://www.youtube.com/watch?v=t8Q7mXdcJ54&feature=player_embedded
hope that helps you
thanks wasn't the information I was looking for but nevermind
I assembled the device now .. but the next problem occured ..
the hd2 is loading without problems (led shows it) but when I try to power it on it's completely dead. nothing happends
with my old touchscreen it was at least possible to power it on.
my question is:
could the new soldered touchscreen + digitizer be broken? or did I break something during disassembly and assembly?
To be honest I didn't see any mistakes I made.
It's not my first time repairing stuff like that because I used to repair notebooks as a hobby.
Still i'm unsure what the heck is going on with my phone atm.
did you check if the flex cable from display is in the port, there is an white stripe that shows how far it must in the port. Did the phone vibrate when you pressed power button?
I checked the cables and found nothing suspicious.
and the phone didnt even vibrate after trying to power it on.
I'm trying to get a new hardkey board (i hope you know what I mean).
Had problems with the keys being stuck and maybe I killed that one by trying to assemble it.
if the phone doesn't recognize me pushing the power on key it's no wonder it won't do anything.
hope this will fix the problem
12dollar said:
I checked the cables and found nothing suspicious.
and the phone didnt even vibrate after trying to power it on.
I'm trying to get a new hardkey board (i hope you know what I mean).
Had problems with the keys being stuck and maybe I killed that one by trying to assemble it.
if the phone doesn't recognize me pushing the power on key it's no wonder it won't do anything.
hope this will fix the problem
Click to expand...
Click to collapse
Most likely something is wrong with your Power button, but you should turn it on with 2nd method:
- pull out battery;
- insert usb cable(connected to PC)/charger in your usb port;
- insert battery.
This way it should turn on whatever OS you have installed on.
If your OS is Android through MAGLDR, connecting it through usb should turn it on by default, unless your battery is not dead!
Check it out!
bib*oops said:
Most likely something is wrong with your Power button, but you should turn it on with 2nd method:
- pull out battery;
- insert usb cable(connected to PC)/charger in your usb port;
- insert battery.
This way it should turn on whatever OS you have installed on.
If your OS is Android through MAGLDR, connecting it through usb should turn it on by default, unless your battery is not dead!
Check it out!
Click to expand...
Click to collapse
I just did as you said and yeah the phone came to life.
so there is definately a dead power button (probably the board is broken)
12dollar said:
I just did as you said and yeah the phone came to life.
so there is definately a dead power button (probably the board is broken)
Click to expand...
Click to collapse
Glad to hear that!
Definitely you should replace your keypad flex!
Did you fix the problem with the hardware keys
Hi,
I have very similar problem.
I changed the touch screen on my HD2 and after reassembling I cannot get the hardware keys clicked.
I ordered a brand new key board and brand new plastic buttons. I received them but situation is the same.
If somebody can explain is there any trick during adjusting the plastic buttons to the clickable "small dots" on the board - please help me.
Best Regards
maznevh said:
Hi,
I have very similar problem.
I changed the touch screen on my HD2 and after reassembling I cannot get the hardware keys clicked.
I ordered a brand new key board and brand new plastic buttons. I received them but situation is the same.
If somebody can explain is there any trick during adjusting the plastic buttons to the clickable "small dots" on the board - please help me.
Best Regards
Click to expand...
Click to collapse
Normally this is always down to glass digitizer not being aligned correctly when stuck to LCD.
0.05mm can make all the difference here.
You need review current digitizer position & pre test assembly to centre chassis without tape for a test run on button function.
Also check button board position is exact & located correctly in the pin holes at each end of the board.
original board quality is normally far better than most of the very cheap eBay pattern parts but one or two sellers offer a decent board around $4.50
Also clean all old tape from back of LCD & centre chassis plate so parts fit flush & once all checked new tape can be added, I also use small spots of up40 adhesive sealant near corners & near middle edges for final build up as holds far better than even the best tapes & gives an original strength & long lasting flush look to final job plus us easily removed with razor blade if repair ever needed again.
Super glue is a BIG no no NO.
Hard to get hardware buttons clickable
Mister B said:
Normally this is always down to glass digitizer not being aligned correctly when stuck to LCD.
0.05mm can make all the difference here.
You need review current digitizer position & pre test assembly to centre chassis without tape for a test run on button function.
Also check button board position is exact & located correctly in the pin holes at each end of the board.
original board quality is normally far better than most of the very cheap eBay pattern parts but one or two sellers offer a decent board around $4.50
Also clean all old tape from back of LCD & centre chassis plate so parts fit flush & once all checked new tape can be added, I also use small spots of up40 adhesive sealant near corners & near middle edges for final build up as holds far better than even the best tapes & gives an original strength & long lasting flush look to final job plus us easily removed with razor blade if repair ever needed again.
Super glue is a BIG no no NO.
Click to expand...
Click to collapse
It is not the case in my case , because I ordered full set (digitizer + display) and they arrived factory assembled.
But you are definitely right - 0.05 mm make the difference. I think the problem comes from the fact that the board with buttons cannot be firmly fixed to the 2 small juts on the chassis. You know the plug of the buttons board is on the tail like extension. Probably when I try to cover the buttons board with the LCD+digitizer - the frame of the LCD slightly pushes the buttons board and the juts on the plastic buttons cannot be fixed exactly on the top of the actual buttons on the board. Anyway we are speaking about precise fixing something around 0.05 mm over something else, which is exactly same size... and in the same time you have to fix this without any visibility.
I will continue trying. If you can give me any other ideas - I will appreciate this.
Thanks
maznevh said:
It is not the case in my case , because I ordered full set (digitizer + display) and they arrived factory assembled.
But you are definitely right - 0.05 mm make the difference. I think the problem comes from the fact that the board with buttons cannot be firmly fixed to the 2 small juts on the chassis. You know the plug of the buttons board is on the tail like extension. Probably when I try to cover the buttons board with the LCD+digitizer - the frame of the LCD slightly pushes the buttons board and the juts on the plastic buttons cannot be fixed exactly on the top of the actual buttons on the board. Anyway we are speaking about precise fixing something around 0.05 mm over something else, which is exactly same size... and in the same time you have to fix this without any visibility.
I will continue trying. If you can give me any other ideas - I will appreciate this.
Thanks
Click to expand...
Click to collapse
Do not rule out the LCD/Digitizer assembly as the china combos are prone to not the best accuracy of assembly as sounds like maybe LCD is mounted just a fraction too low on the digitizer perhaps.
Button board should be fixed via 3M style tape & most replacement boards come with tape ready for fitting.
worth making effort with button board to centre chassis to mount securely then mounting lcd to chassis without tape for a trial assembly & try and check for possible issues such as bent chassis or old tape not removed sufficiently or new assembly alignment not the best.
I would also recommend using original plastic button strip as the copy ones are not always good & have had experience with them before.

[Q] New screen not working after replacement

Hi all,
I had a touchscreen issue (sometimes not working) in my HD2 so I ordered a new fabric screen+lcd assemby. I replaced it very carefully but now when I plug new lcd it is not working. Phone is working, buttons, vibration, hear the sound when turning on but there is only backlight on display and just shows black screen. I am sure that display is ok because I tried to put old one (wich was still working before replacement) and it has same issue (backlight works but display is black). Can you give me some ideas what is wrong ????
damaged lcd ribbon connector on mainboard or ribbon not being inserted fully or latched securely
Ty booting to bootloader ...
Help
The flex cable is not attached correctly or the main board is broken and before you close your phone try it. If you can't do this give someone your phone and he will recover for you.
The problem is sloved. I dissasambled all phone and fix it once again and now it works. Anyway I got another problem of white screen on my second device. Did anybody find a solution for white screen ever????
wojcimierz said:
The problem is sloved. I dissasambled all phone and fix it once again and now it works. Anyway I got another problem of white screen on my second device. Did anybody find a solution for white screen ever????
Click to expand...
Click to collapse
Have you tried turning phone on with volume down button pressed???
You should see 4 colors. Try this. I search for you.
http://forum.xda-developers.com/showthread.php?t=2263026
try with this link.
Yes I have read this before but I think that white screen problem is not sloved in this thread. But maybe I could be wrong.

Erratic touch screen after digitizer + LCD replacement

Hello,
I replaced the digitizer and LCD on my 1st generation Nexus 7 with an apparently identical Hydis LCD/digitizer assembly. Now I am experiencing erratic behavior of the touch screen, some dead spots, scrolling registering as touch, etc.
Could this be a grounding issue that happens now because I did not properly put the unit back together? If so, which areas should I focuse on / cover with electrical tape to try and get rid of the issue?
Could this also be a software issue if the lcd/digitizer model is not exactly the same? The numbers below the "Hydis" markings are the same as on the original unit, but the numbers below the code bars are different. If so, is there a solution? Drivers? Calibration?
Thanks in advance for any insight.
daviddema said:
Hello,
I replaced the digitizer and LCD on my 1st generation Nexus 7 with an apparently identical Hydis LCD/digitizer assembly. Now I am experiencing erratic behavior of the touch screen, some dead spots, scrolling registering as touch, etc.
Could this be a grounding issue that happens now because I did not properly put the unit back together? If so, which areas should I focuse on / cover with electrical tape to try and get rid of the issue?
Could this also be a software issue if the lcd/digitizer model is not exactly the same? The numbers below the "Hydis" markings are the same as on the original unit, but the numbers below the code bars are different. If so, is there a solution? Drivers? Calibration?
Thanks in advance for any insight.
Click to expand...
Click to collapse
Turns out I had not fully reinserted the digitizer ribbon connector into the mobo clip connectors. The white lines on the ribbon connector should be exactly flush and parallel with the black part of the clip connectors, and you should hear/feel a light click when they get fully inserted. Works fine now!

Multiple issues with Joying JY-UL135N2

I have a JY-UL135N2 unit in a Toyota Fielder 2012. The screen of the unit was damaged during installation and I bought a new screen from Joying. The screen assembly was attached to the rear assembly with just one ribbon cable that came with the new screen.
Currently I have these issues:
1. Screen brightness control does not work.
2. The unit does not shut down when commanded by the nob or the pull-down from notification bar.
3. The unit stays on for 4/5 minutes after I have switched off the car and locked it.
My questions are:
1. Is the screen panel supposed to be connected via 2 ribbon cables? if yes where can I by the second cable.
2. Are the issues I mentioned normal or I'm the only one facing it.
3. Could there be any installation issue that is causing these problems?
The unit has been updated to the current software version and had been factory reset twice but the issues remain.
ROBINGAZI said:
I have a JY-UL135N2 unit in a Toyota Fielder 2012. The screen of the unit was damaged during installation and I bought a new screen from Joying. The screen assembly was attached to the rear assembly with just one ribbon cable that came with the new screen.
Currently I have these issues:
1. Screen brightness control does not work.
2. The unit does not shut down when commanded by the nob or the pull-down from notification bar.
3. The unit stays on for 4/5 minutes after I have switched off the car and locked it.
My questions are:
1. Is the screen panel supposed to be connected via 2 ribbon cables? if yes where can I by the second cable.
2. Are the issues I mentioned normal or I'm the only one facing it.
3. Could there be any installation issue that is causing these problems?
The unit has been updated to the current software version and had been factory reset twice but the issues remain.
Click to expand...
Click to collapse
I don't have all the answers, but I can tell you mine frequently takes a similar time to shut down. I don't know if you need a cable but Digikey has a large variety of flex cables. Does it work to set screen brightness from the Settings screen instead of from the launcher?
xdamember2 said:
I don't have all the answers, but I can tell you mine frequently takes a similar time to shut down. I don't know if you need a cable but Digikey has a large variety of flex cables. Does it work to set screen brightness from the Settings screen instead of from the launcher?
Click to expand...
Click to collapse
I have recently unplugged the HU and plugged it in again... it has reduced the shutdown time to under a minute. From what I have learned from the Joying forum is that this unit like a few others comes with one single flex cable connecting the screen and the back end.
Screen brightness does not reduce, no matter what I do. It is always at full brightness.

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