How to diagnose hardware when the display is not working? - Xiaomi Mi A2 Lite Questions & Answers

Hi,
My son dropped the device in drinking water. I opened the case, separated the battery, and kept the device inside rice for 3 days straight. Now, I don't see any trace of water. When connecting the USB cable, with ultimeter, I see the battery charging. I connect the battery and try to turn it ON. The device responses with vibration and the display back light is lit. However, there is nothing in the screen, it's completely off. The screen back light is always ON when charging.
How to diagnose the hardware in this condition (as the display is not working)? Is there any PC application for this device that can do the full hardware test? What should be my next steps to figure out what might be broken?
Thanks in advance.

Related

Screen dead from minor water damage. Help?!

Short story...this weekend I had my Gnex about 2 feet from a hot tub and was periodically changing songs on it, getting drops of water on the screen and sometimes wiping it off with a towel. Fast forward to an hour after leaving the hot tub (with a fully functioning phone) and my battery dies during a phone call. I plug in the phone (powered off) and a few hours later turn it on to see the screen black/white fuzzy like a tv without reception. I restart but see the same. I pull the battery and shove it in rice for a day... the phone vibrates upon powering up but now nothing at all shows on the screen. I dismantled the phone today and saw the water sensor attached near the charging port is pink. Any thoughts on how I can salvage the phone? My computer recognizes the Gnex but the folder appears completely blank. This phone has been through much worse, I can't believe small droplets on the screen did this. Thanks in advance for any advice.

Phone shut off, won't turn back on no matter what, blank display/GreenBlue LEDs HELP

Hello all. I recently made this thread where I described the phone, the LG G3 d851 t-mobile variant. randomly rebooting and not turning on without pulling the battery. (http://forum.xda-developers.com/lg-g3/help/d851-randomly-shuts-off-wont-power-t3424458). I deduced it to the replacement battery (supposedly genuine) that I purchased from a seller on ebay. I put my old battery in and everything is fine again, and the seller shipped me another replacement battery (big mistake, i know).
I put in the replacement battery, and a day later the phone shuts down again in the same manner as stated in the previous thread. I pull out the battery and put it back in and.. nothing happens on screen. The LEDS just flash green and blue. I tried plugging it into a charger, just a red LED, no display. If I plug in the phone to a charger without the battery inserted, the backlight activates but nothing whatsoever appears on the screen. I cannot get into the recovery either.
If I let the phone sit for a while, and try to power it on, I see the LG boot screen appear for about 5 seconds. Then the image flickers and fades away to black, and the LED just flashes blue/green.
Am I screwed or is there any way to salvage this phone? I'm desperate for any assistance and I'm totally open to any component level repair you guys recommend (I'm pretty broke :/)
Thanks all!
Current behavior:
Attempt to turn phone on: Blank display, no backlight, blue/green LEDs
Plug phone in with battery in: Blank display, no backlight, red LED
Plug phone without battery in: Blank display, backlight active, red LED
Do any of the above after leaving phone off for a while with battery unplugged: display begins to display the expected image for 5 seconds, then the screen flickers and the image fades until the screen turns black.
I tried the old (working) battery, and no luck either.
[edit] Hopefully solved. please read my latest post for my idiotic but somehow functional solution
amaskedman said:
Hello all. I recently made this thread where I described the phone randomly rebooting and not turning on without pulling the battery. (http://forum.xda-developers.com/lg-g3/help/d851-randomly-shuts-off-wont-power-t3424458). I deduced it to the replacement battery (supposedly genuine) that I purchased from a seller on ebay. I put my old battery in and everything is fine again, and the seller shipped me another replacement battery (big mistake, i know).
I put in the replacement battery, and a day later the phone shuts down again in the same manner as stated in the previous thread. I pull out the battery and put it back in and.. nothing happens on screen. The LEDS just flash green and blue. I tried plugging it into a charger, just a red LED, no display. If I plug in the phone to a charger without the battery inserted, the backlight activates but nothing whatsoever appears on the screen.
I tried the old (working) battery, and no luck either.
If I let the phone sit for a while, and try to power it on, I see the LG boot screen appear for about 5 seconds. Then the image flickers and fades away to black, and the LED just flashes blue/green.
Am I screwed or is there any way to salvage this phone? I'm desperate for any assistance and I'm totally open to any component level repair you guys recommend (I'm pretty broke :/)
Thanks all!
Click to expand...
Click to collapse
It would help if you would say what variant you have (at&t, verizon, sprint). Can you boot into TWRP? If your able to get into bootloader kdz or tot back to stock.
netookska05 said:
It would help if you would say what variant you have (at&t, verizon, sprint). Can you boot into TWRP? If your able to get into bootloader kdz or tot back to stock.
Click to expand...
Click to collapse
Sorry! I am using the d851 T-mobile model. I can't boot into recovery or anything. the LED just flashes some color but nothing appears on the screen.
Behavior:
Attempt to turn phone on: Blank display, no backlight, blue/green LEDs
Plug phone in with battery in: Blank display, no backlight, red LED
Plug phone without battery in: Blank display, backlight active, red LED
Do any of the above after leaving phone off for a while with battery unplugged: display begins to display the expected image for 5 seconds, then the screen flickers and the image fades until the screen turns black.
Will update the OP
Thank you for the reply.
amaskedman said:
Sorry! I am using the d851 T-mobile model. I can't boot into recovery or anything. the LED just flashes some color but nothing appears on the screen.
Behavior:
Attempt to turn phone on: Blank display, no backlight, blue/green LEDs
Plug phone in with battery in: Blank display, no backlight, red LED
Plug phone without battery in: Blank display, backlight active, red LED
Do any of the above after leaving phone off for a while with battery unplugged: display begins to display the expected image for 5 seconds, then the screen flickers and the image fades until the screen turns black.
Will update the OP
Thank you for the reply.
Click to expand...
Click to collapse
Possibly bricked plug it into your computer and see what it comes up as.
So strangely enough, I tried heating my phone using the most idiotic method possible by letting it heat in my blanket (I don't have immediate access to a heat gun). The screen began displaying some funky artifacts when attempting to boot with the LG logo but would otherwise revert to the behavior described in the OP (only LED working, no LCD display.).
I let the phone cool for a few hours and I'm actually able to get as far as the dialog box where it asks you whether or not you really want to format, in other words the factory data reset dialog box (when holding vol down + power to get into the recovery) with minimal to no hardware artififacts., and only when I confirm that I do does it crap out and revert to the previously described behavior. But it actually lets me use the vol keys to select an option, so I'm getting a lot further than before.
So this absolutely seems to be a hardware problem. Anywhere you guys suggest I examine before I take a heat gun to the motherboard? Any specific component I should look at?
Thank you guys so much
Take it to certified technician he will fix ur device these phones are dirt cheap nowadays so u will not be charged heavily no more than 50$ worthl
So,
after reading into this more and suspecting loose solder joints (see the various threads about screen flickering problem), I decided to pursue this route and continue trying to heat the logic board.
I'm completely broke and don't have access to a heat gun, and with no other working phone I decided to take some desperate measures. For those of you having a similar problem and reading this, PLEASE DON'T ATTEMPT WHAT I'M ABOUT TO DESCRIBE. THIS IS A HORRIBLE IDEA.
I turned on the phone to get the blue/green LEDs , plugged it into the wall, and wrapped the phone with blankets. I let the phone cook itself for 2 hours.
Yes, just like the infamous xbox 360 "towel trick".
When I went to remove the phone from my makeshift blanket oven, the phone was brutally hot and felt like a stovetop (was painful to touch for the first 30 seconds). The screen was filled with artifacts due to the intense heat.
I carefully removed the battery, let the heat dissipate slowly for a couple minutes, let the phone cool on an AC unit for a another few minutes and turned the phone on.
It worked. Phone boots and haven't had a single problem for over a day.
I guess the problem was cold solder joints after all, and the intense heat was enough to reflow the solder and form a stable enough connection to allow the display to function again.
Even ran a stress test program for an hour with no issues.
Hoping this fix lasts (knock on wood), will report back if I have any issues.
Again, anyone having a similar problem, please don't emulate me. I shouldn't even have to say why this is a bad idea. Get a heat gun, remove the motherboard and heat it that way.
I'm sure applying the proper repair procedure described in this thread http://forum.xda-developers.com/lg-g3/help/screen-flickering-fix-successful-t3397411 would have fixed my problem as well.
So, why did this problem happen in the first place? I'm guessing it has to do with the overheating issues this model of phone has (at least my particular unit). I've been playing a lot of pokemon go, so the phone is running a lot hotter than it used to. The constant high temps (reading upwards of 75c frequently from my cpu) were enough to weaken the solder joints. I also recall dropping the phone a couple times while playing the game, and I guess this was enough to knock the joints out of wack.
I'm currently capping the CPU at 1500mhz and the GPU at 300mhz and the phone is running a lot cooler now. I'm probably going to set the resolution to 1080p, cap the framerate and possibly undervolt, though this might not be necessary.
Thanks for reading and hope this helps someone in the future.

Water damage

Hi
Got a water damaged nexus 7 2013 over here, as soon as it was dropped in water, I turned it off and dried it off before taking it apart and letting it dry out. After putting everything back together the tablet worked wonderfully and the only remainder was a little bit of water under the touch screen and I think I made a big mistake by ignoring that.
After about a week, the battery was dead and needed to be charged, I plugged it in and the led blinked 5 times which is normal so I just left it. After coming back I noticed that the tablet was pretty hot near the cpu and of course, it refuses to turn on, it doesn't blink 5 times anymore, my computer doesn't beep anymore, it's totally dead.
Things I've tried so far:
Connecting it to my pc without battery and screen connected (I know it should blink 5 times as well if no battery is installed) and nothing
Trying to turn it on without daughter board connected (should still show google screen, I have done this before) and again, nothing
Trying to turn it on without screen or daughter board (I know I had a notification that made it beep when it turned on) and nothing
I took it apart again and noticed that the connector on the actual lcd was very corroded and I just assumed the screen was causing this but apparently something else is broken as well.
Anything I can do about this?
Thanks
Hi, I'm sorry to hear about this unfortunate accident.
Firstly an advice to anyone reading it -- in such situation, turning it off is not good enough and one must disconnect the battery ASAP! That's because the power switch is actually only like a standby control and unable to completely cut off power supply. While off, full power is still available to all mobo's voltage regulators as well as LCD's backlight converter and its local power regulator. And then accelerated water corrosion and damage starts...​Remove all metal shields from the motherboard and clean up corrosion residues. The LCD is gone for sure, so test it out again with the mobo and peripheral boards only, looking for the notification light's blinks. If it works, check if you can get picture over SlimPort connection.
:fingers-crossed:​
k23m said:
Hi, I'm sorry to hear about this unfortunate accident.
Firstly an advice to anyone reading it -- in such situation, turning it off is not good enough and one must disconnect the battery ASAP! That's because the power switch is actually only like a standby control and unable to completely cut off power supply. While off, full power is still available to all mobo's voltage regulators as well as LCD's backlight converter and its local power regulator. And then accelerated water corrosion and damage starts...​Remove all metal shields from the motherboard and clean up corrosion residues. The LCD is gone for sure, so test it out again with the mobo and peripheral boards only, looking for the notification light's blinks. If it works, check if you can get picture over SlimPort connection.
:fingers-crossed:​
Click to expand...
Click to collapse
I used a multi-meter to test the battery and the cells are @ 3.4V not sure if that's enough to turn the tablet on tough... I'm letting it charge for a while now to see if my computer picks it up
EDIT: the battery voltage when not connected to the board is 3.4V, the battery voltage when connected to the board is 0.34V. That can't be good
EDIT2: the cpu is mildly warm but the PM8921 battery management IC is burning hot after leaving it to charge for a while

Major Battery Issues

Hello everyone,
I have a major issue regarding battery.
Here is a rundown of what has happened.
1. There was moisture detected at first by the sensor and there was in fact moisture there after I plugged in my usb charger in and saw water around the usb-c connector. This was due to humidity most likely as I live in NJ.
2. I cleaned it out with a cue tip at first and nothing changed. Plugged my usb charger back in to see if water was around it which it was not obviously.
3. Left my phone on overnight and then the Icon went away but, I could not charge my phone anymore despite their being no notification showing me that the phone was incapable of being charged because of "x" reason. I also made sure to use a shop vacuum to remove any other residue inside the phone.
4. Turned my phone off and then I was finally able to charge it.
5. Turned it back on and then the issue I have now is happening along with the fact, when I use my charger that came with the phone, I get a notification that I should use the charger that came with phone if I want it to charge faster....
Not only that but, to get it to charge occassionally I had to turn airplane mode on and THEN it would charge. This is spotty because it works sometimes, sometimes it doesn't.
Today I hit a breakthrough. After doing a factory reset (that literally did not change anything at all. Same problem, despite everyone at reddit suggesting a factory reset) I loaded my back up file that I created before the factory reset and *poof* the issues described above vanished.
However. When I put my phone into airplane mode and turned it off (tried to mimic the most successful variables that allowed me to use the phone without issue) and then plugged a my usb cable in, it charged no problem. Then when I turned the phone back on, the evil bleeping and screen dimmer of death came back on.
I am not up for a loaner phone and I can not wait 2 weeks for a new phone seeing as I work and people are always calling me.
Recommendations?
What do I do if no one responds?
Bump?
Not sure what else you can do. Sounds like the port got shorted out partially. I suggest grabbing a Qi charger and going that route in the interim, that should work without issue, unless the circuit on the board is the issue and not the USB port. I assume you are using a different chable/charger than the one that was wet?
Davetheboss said:
Hello everyone,
I have a major issue regarding battery.
Here is a rundown of what has happened.
1. There was moisture detected at first by the sensor and there was in fact moisture there after I plugged in my usb charger in and saw water around the usb-c connector. This was due to humidity most likely as I live in NJ.
2. I cleaned it out with a cue tip at first and nothing changed. Plugged my usb charger back in to see if water was around it which it was not obviously.
3. Left my phone on overnight and then the Icon went away but, I could not charge my phone anymore despite their being no notification showing me that the phone was incapable of being charged because of "x" reason. I also made sure to use a shop vacuum to remove any other residue inside the phone.
4. Turned my phone off and then I was finally able to charge it.
5. Turned it back on and then the issue I have now is happening along with the fact, when I use my charger that came with the phone, I get a notification that I should use the charger that came with phone if I want it to charge faster....
Not only that but, to get it to charge occassionally I had to turn airplane mode on and THEN it would charge. This is spotty because it works sometimes, sometimes it doesn't.
Today I hit a breakthrough. After doing a factory reset (that literally did not change anything at all. Same problem, despite everyone at reddit suggesting a factory reset) I loaded my back up file that I created before the factory reset and *poof* the issues described above vanished.
However. When I put my phone into airplane mode and turned it off (tried to mimic the most successful variables that allowed me to use the phone without issue) and then plugged a my usb cable in, it charged no problem. Then when I turned the phone back on, the evil bleeping and screen dimmer of death came back on.
I am not up for a loaner phone and I can not wait 2 weeks for a new phone seeing as I work and people are always calling me.
Recommendations?
Click to expand...
Click to collapse
Try leaving your phone all night in Rice. The rice absorbs moisture from the phones when they fall into the water.

need help with charging problem

Hi,
Even after I fell into some water with my phone in my pocket (dumb, I know), after a day of drying out, the phone came back to life and seems to work fine - except.... it won't charge when the phone is turned on. If I leave the phone off, it charges. Turn it on (recovery mode or regular mode), and it won't charge. Anyone have any ideas if this is fixable? Should I replace the small PC board with the USB port on it? Or replace the phone?
Thanks!
I think the phone will not be replaced as it is water damaged

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