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DIAGNOZED Pipo M3 "old PCB/firmware" and freezing issues


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#1 Vytasbcn

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Posted 20 December 2012 - 02:33 PM

Now I bought 4 of them for X-Mas presents. Arrived 2 days ago.

1st of them misbehaved and froze when AnTuTu Benchmark was started. I thought I just got unlucky and thought about software/firmware issues.
Today tried the other one and it was fine - no problem.
Started looking into the kernel numbers, read some of your forums... But it did not make 100% sense what I was reading, so I finally decided to open it up: used very fine blade knife first to pry it up from the corner far from the volume control and then inserted old credit card to keep it on till the other side - carefully for not to crack the plastic or not to scratch.

Here is what I found (1st image):


Then I just could not understand: people are saying old PCB has problems, as the flash fixes problems for new PCB... But mine is new PCB... Then people were running at lowest speed with old firmware while others had crashes or touchscreen not working...

So I decided to open up the one that was working (second image):

And surprise surprise I HAVE THE DIAGNOSIS!

Does anyone of you see the difference yet?!

To confirm my suspicions I have opened up all of them and it was confirmed (3rd image):

Now the PROBLEM of all the freezes and touchscreen stopping working is very easy - HEAT, and in that particular case is OVERHEATING.

If you notice the PCB by itself is the same, there are the same elements and chips on the board, but the difference is that the tablets built after 30-08-2012 all of them would have the miniheatsink from the metal, than you could see soldered and with thermal pad between it and the CPU + GPU, then plus metal pads for it to touch that fine aluminum backpanel to get the heat off the chips. That is what the previous builds are lacking - no proper heat-sink, just thermal pad and then no proper contact with the back panel.

Believe me the chip gets HOT just a moment you start running a benchmark and obviously it crashes as it overheats.
If you what experimental data - just touch on the heatsink over it when running benchmark - at the end you would like to keep the finger away and not get burned :-D


SUGGESTION: if you have a problem so then open-up your tablet and prepare to fill that space between the chip and the back panel with extra thermal pads and metal meshes.

I will keep you informed later and probably after X-mas when I would get those materials and try to fix it.

And here you may look at other photos and see that all of them have NEW PCBs and different versions of them. there is only one of them with different build and there is only one of them that crashes.

Feedback would be very appreciated!! :-D

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#2 adymole42

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Posted 28 January 2013 - 01:36 PM

hi i paid for a pipo m3 off ipadalternatives it took 4 weeks to arrive when it did it crashed after 10 mins of use the only way i could use it for a bit is if i restarted it the strangest thing is i put it on the other day and it lasted over an hour then the screen froze what happens the screen froze and the wording went i bit blurry could anyone please help ?

#3 meujoystick

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Posted 29 January 2013 - 03:08 PM

Hello, could you tell which of these models works with more stability? Some of the PCBs Wifi and 3G does not work properly? I ordered my M3 Pipo 3G Version, this link
Will I have problems with it?
This is the 7.4V 3500mAh.

#4 Uttam S

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Posted 23 March 2013 - 12:30 PM

Thanks Vytasbcn!

I was able to get a more stable operation by fixing heatsink in my PiPO M3 3G.

I had received my PiPO M3 3G in December 2012 and from the beginning I was having freezing issues. The freeze would happen mostly in either of the 2 ways:

1. Screen content becomes jagged (kind of combing pattern) with a brief 'cheeeen' sound from the speakers
2. Screen will go blank with a random color - white, green, etc.

I had tried all solutions I could think of (thanks a lot to slatedroid.com for all the guides and tips) - updating different firmwares, trying different combinations of settings, disabling programs, and I was getting the same issue and it was driving me crazy!!

I noticed that the front of screen towards the middle right used to get hot..which led me think - is it that the processor heat is not getting dissipated properly - it should make the back metal case hot not the front screen. So armed with different tips on PiPO M3 from more experienced users, I opened the tab one day (alas! lost my 32gb micro sd card in the process as I forgot to remove it before opening the tablet) to see if the heat sink as shown in this thread is there - and it was there indeed. There are 3 bushes on the heatsink and corresponding white patches on the back panel which are supposed to transfer heat to the back panel I suppose. Also, I felt that one corner of the heat sink was not properly in contact with the component underneath.

First I tried putting extra bushes between heatsink and the back panel and for a day it seemed like it made a difference but soon I was back to frequent freezing.

Then I decided to do something more drastic, as I was convinced that the heatsink is not cooling the processor properly. I ordered few items - a copper heatsink of the size of the processor, heatsink paste, and heatsink pad from ###########. Then I opened the tablet and remove the soldering from the different corners of the heatsink and finally managed to get it off. AND GUESS WHAT - there was a blue color plastic film on the heat sink!! This film would never let the heatsink to come into proper contact with the processor. The processor had white color 2-3mm think thermal pad and then on top of it heat sink was installed. I removed that thermal pad and put the thermal pad (very thin) and copper heatsink that I had procured. The new heatsink was almost the same thickness as the white thermal pad previously installed. Therefore, I could managed to solder back the stock heat sink also. I put some extra bushing made from rolled aluminium foil on the heat sink so that there is better thermal contact with the back panel. Sorry, I forgot to take pictures during the whole process :(

After this fix, my tablet is much more stable but not 100% freeze free. I still get freezes but it is not so frequent.

Below are the links to items that I had procured:

Attached is the image that I have taken from this thread and added my comments, since I forgot to take my own pictures. Also attached is the photo of plastic blue film that I removed from under the heatsink and the white thermal pads that were mounted on CPU and adjacent chips (RAM?). Note that I had cut a small part of one of the pads and used it on a small chip that I found to be getting hot.

PLEASE REMEMBER TO REMOVE SIM CARD AND MICRO SD CARD IF ATTEMPTING TO OPEN THE TABLET. I DAMAGED MY 32GB MICRO SD CARD WHILE OPENING THE TABLET :'(.

Kind Regards,
Uttam

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Edited by Uttam S, 24 March 2013 - 12:07 PM.