poco m3 does not turn on anymore

[baxir]

I would recommed you that try to flash the recovery ROM using ADB, thats the possible way I can think of.

 

[Dheerajvirgo]

which MIUI update are you on?

 

[Dheerajvirgo]

after updating to miui 13 for the first time. i rebooted but it is still dead. no message of waiting for upgrading ur phone dont turn off. even after draining battery process it is not opening to upgrade process screen.

were you able to get your phone working or boot properly?

 

[xaadilhx]

Can't believe this thread has continued this much. I encountered this error on my m3 crash black screen. Always needed to avoid turning off, running out of battery etc or goes to black screen.

Previously messed with software, Edl stuff and eventually today decided either trash the device or try removing the shield as didn't use device properly for a year.

Used a heat gun, heated and removed the shield perfectly, with the heat, I thought it'll break but I'm surprised

worked perfectly when connected. Finally can use the device again. Updated mui 13 then 14, rebooted, powered off, all back to normal so stupid issue but that issue was such a pain.

 

[piccolo132]

@sarabbafrani
Can I fix the no 3g/4g issue caused by bad ic solder doing a reflow?
If so, what temperature should I use and for how much time? (air soldering gun)

 

[sarabbafrani]

@sarabbafrani
Can I fix the no 3g/4g issue caused by bad ic solder doing a reflow?
If so, what temperature should I use and for how much time? (air soldering gun)

power envelope tracker ic
that small ic under shield
misaligned or damaged
should rebal or swap ic

 

[piccolo132]

power envelope tracker ic
that small ic under shield
misaligned or damaged
should rebal or swap ic

@sarabbafrani
i'll expalin to you what happened exactly:
i did remove the shield and the 2 capacitors, because only removing shield wasn't working for me, then i reassembled the phone and it worked for 3/4 months, then 3g/4g stopped working ( i can still scan for 3g and 4g networks and see them listed, but it won't connect to them) it's stuck in 2g.
so i was wondering if a reflow of that ic would fix it or i need to replace that ic?

 

[rotoko]

@sarabbafrani
i'll expalin to you what happened exactly:
i did remove the shield and the 2 capacitors, because only removing shield wasn't working for me, then i reassembled the phone and it worked for 3/4 months, then 3g/4g stopped working ( i can still scan for 3g and 4g networks and see them listed, but it won't connect to them) it's stuck in 2g.
so i was wondering if a reflow of that ic would fix it or i need to replace that ic?

If you're already in this area, the only thing left to do is throw away the phone and buy a new one.

 

[rotoko]

Poco m3 drains battery by itself. General rule of the thumb
1-10% - 0 to 1 day
11-20% - 2 days
Basically 1 day is around 10% of battery

I think the motherboard is on but for some odd reason the display board and basically the whole thing doesnt turn on on. But it still is draining battery even when turned off. Removing the battery doesnt fix it. I tried several times

If you're already in this area, the only thing left to do is throw away the phone and buy a new one.

 

[roborob999]

Hi.
I had the blank screen problem, then solved it in an unexpected way. No time to read through the forum here, so it may happen this solution already exist. Just my two cents.

Problem.
Poco M3 suddenly would not turn on, just vibrates, total black screen. I had already sent it back once under warranty about a year ago, as it had the post-update problem, I assume they change a part back then, but it had been working fine since then.

Tried:
Holding power, holding power and up or down volume, all I would ever get was a half second vibrate. Also I opened it up and disconnected both battery connectors, still did not work (although, I was thinking I could have left it disconnected for longer than the thirty seconds I did, in case there were some capacitors to discharge). All for nothing. Over about a week I would randomly try holding various power button combinations, always same hlaf second vibrate. I did not try a total discharge.

Solution:
I was thinking maybe if the digitizer is broken, I can connect through a usb-c dock to a monitor and mouse, and see what I can recover that way. So I plugged phone in a Lenovo travel dock, (article 4X90S92381), HDMI into a monitor, and also a 65w power supply into the dock. Tried powering on, nothing came on the computer monitor, but after about a short while the phone just started up like normal. Crazy times. Also, I noticed after that the 65w power supply was not actually switched on at the wall. Phone battery was at 80% when I turned on. Since then the phone has worked like normal.

I hope that helps someone.

 

[roliviu]

I removed the shield, but when I put it to charge it vibrates and lights up continuously, it doesn't turn on or charge.

 

[qunguwueguewue]

Hey! I also have this problem, what's the general consensus on how to fix this? Right now I can access it since I sent it to the repair shop so I could use it again, but I don't know how much longer it can last.

 

[goriath]

Hi everybody,

I would like to share my experience.
3 days ago one of my family members reported her POCO M3 suddenly turned off (about 50% battery) and then never turned on again. Pressing pw button for long time, combination with VOL-/+, all 3 buttons at the same time, nothing worked. Connected to the charger neither, no charging mode; totally dead.
I tried also to link the phone to a PC with the USB cable and in windows was detected as QUSB_BULK_CID:041C_SN:AD09F802 device but the phone display stayed black, nothing else.
Xiaomi service support confirmed that the phone was out of warranty (by only 3 months, meh!)

I opened the phone and put aside the back cover with fingerprint sensor, so I measured the battery and found it rock solid at 3.8V, so my guess the battery was good. I also measured voltage and current through a USB meter during the charging and @5V the current flow sticked to 80mA, so no charging at all. I found a video on youtube that suggest to detached the battery, try to use the charger again and then reconnect the battery. I did it, I detached the battery and connected the charger, the phone powered on this time, with the icon of a battery with a bolt inside only for a while, then the display turned black again. Then I reconnected the battery and I made sure that the ribbon cable coming from the USB port to the motherboard was conncted properly, so I disconnected and reconnected it.

It worked! The phone turned on again. I performed several reboot, switched off and on again, everything as usual. So after turning it off again I was happy to reassembly the phone, but after I finished to clean it as new, as soon as I turned it on again the phone didn't show any signs of life. Turned dead again!! Although I did again everything from the start, it turned out that the battery trick didn't work anymore...

I spent a whole day with the phone teared apart on my desk, no matter how much I tried, it never turned on again. So I found this thread which I read entirely, where the main hint is to remove the tiny shield from the back of the motherboard, since the big cap (actually it's an inductor!) underneath, heating itself, gets bigger and goes to touch the shield causing a short...
I was very skeptic about this explanation; how could it be as such design flaw?!

I watched several youtube videos in which removing the tiny shield was involved, but those indian technicians were also removing components too. Someone replaced the big cap inductor, other removed completely the two tiny caps...why? I can't understand.

Other videos involved reflow/reball the power management IC in the next shield in the middle (this made more sense to me, but I remembered that with the battery detached the charger powered on the phone with charging icon on screen, so that must have meant something - more likely a working IC in my case), even someone reworked ARM CPU and NAND flash in the third shield. I didn't know what to try, it was overhelming.

At last I decided myself to go for the @sarabbafrani suggestion, so I picked up my new hot air SMD rework station (never used one before, first time), my smd tweezers and silicon mat. I wrapped the motherboard with a safety shield made of aluminum kitchen foil and kapton tape (oh well it's about clear green PET tape, I don't think it's real Kapton since it was very cheap although it was advertised as such; in china they call it Koptan I think), keeping out only the affected area which I flooded with two flux drops (I made this one by my self at home).
Set the temp of the station to 380°C, the air flow to 40% and mounted 5mm nozzle - I kept the tiny lid between the tweezers while lifting slightly the PCB from the silicon mat, while heating the part it took me less than 10 seconds to remove it perfectly vertical while the PCB fall down on the mat under its own weight. It came off so easy and neat, no spread of solder, perfectly clean after some IPA.

I changed thermal pads with new high performance ones, reassembled the phone, cleaned it, shutted down and restarted it so many times that I forgot...

It - does - work, simple and plain (it's finally charging right now)

So at this point I would share some dimensional findings
I took my caliper and this is what I got:

Tiny lid height is 1.5 ~ 1.55mm
Tiny lid inside quote is 1.3mm (so its thickness is 0.20 ~ 0.25mm)
Cap Inductor height (big black one) is 0.95 ~ 1mm
PCB is 0.75mm - while the tiny lid + PCB (still soldered) whole assembly is 2.3mm overall

So room between cap inductor and the top inside the lid is about 0.35mm (MIN 0.3mm / MAX 0.4mm)
Now the question for @sarabbafrani is: could really an SMD component, a cap inductor in particular, under thermal environment grow so much to hit that metal part??
I think 0.35mm is a lot of space, isn't it?

I made also a different consideration; since 0.35mm is more likely mechanically enough, but still very close to the metal lid, it could be about arcing instead of touching?
I mean, the cap inductor can't grow enough to physically touch the lid (if actually does...), but it can come close enough to establish an electrical arc between itself and the metal lid...
Think of contacts switches or relay; while closing (or opening) breakdown voltage of the contacts gap is reached and exceeded, the air between electrodes is ionized, temp raise, a voltaic arc is started.

We might be dealing here with a capacitive inductive load, stored energy in the cap inductor which acts like a trigger; does it actually make any sense?

EDIT: found the diagram about the M3 PCB and discovered that SMD component supposed to hit the metal lid it's actually an inductor NOT A CAP; L3801 on schematics!

 

[tvhex]

I'm facing a strange issue with my Poco M3 today. The lock screen had characters and numbers. Yesterday, I noticed that the characters are not appearing, so I can't enter the password. The most important thing is that there are numbers from 1 to 9 on the screen, but 0 is missing.

Now, how can I unlock the lock? And there's no "Forgot Password" option below. If it were there, I could unlock the lock using my account.

There's a mobile death problem on Poco M3. When I turn off the mobile power, the phone doesn't turn on. Although I've found a temporary solution for it. But it doesn't go to mobile recovery mode. And once the phone is turned off, it doesn't connect to the laptop either.

 

[Sissou83]

Hi,
and your POCO M3 still works?
I don't have an air gun for desoldering, but I have a soldering iron, do you think I can desolder with it?