GTA02 power death

Dmitry Shalnoff shalnoff at
Sun Dec 23 06:15:02 CET 2012

Hi everybody,

The situation:
I've use for a couple of month this battery

yesterday my device accidently start switching off (after night 
recharging) and make some strange buzzing on power on without any 
visible activity (screen was kept black). So I decide that is a known 
"complete battery drain" problem and try to animate the device with 
external power.

However, after several attempts I've got it booted. The screen picture 
was surprisingly inverted (!) but after sleep and awaking procedure it 
gets normal.

After that, I've got idea to measure the battery voltage and found that 
it is 4.1 v (instead normal 3.7). Eventually I deside to leave it as is 
and try to find the cause at morning. I switch it off and go to sleep.

Today I repeat operation with all similar symptomes (noise on power on 
without any other reactions) but without any success. Contrariwise, 
after several iterations of unsuccessful tries, when I power it on with 
battery and original USB adapter, it suddenly turned on for the second, 
then screen start gets brigther and finally I feel sweet smell of 
burning isolation :) I immediately remove all power sources, disassemble 
the device and found that I've burned some tiny IC near the PCF50633HN.

The question:
I digg all internets regarding the PCB layout but can't find anything 
relevant (there is no PCB layout on the wiki?). I suppose that was 
RT9013 (at least that only component in this schematic block that has 
similar package) but I'm not sure. Could anybody help me to identify 
this component?

here is HiRes picture of the patient
You easily find it by burning fume around it :)

except of that would be intereting to get some hints what the real 
reason cause this situation. And why LiPo battery can start to show 
4.1v?  I suppose that has some connection to the charging procedure (I 
use QTmoko without the non-original battery patch).

Thank you for any hints in advance!
Plan to purchase and resolder it.


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