820-01521 A1932

[TBFix]

Looks like there was little spillage around q7660. PPBUS_G3H goes between 12.2 and 12.6v. Current starts at .100ma then works to 400ma for a second then drops back to 100ma. Nothing visibly getting warm except t2 which is at around 40c.
PP5V_G3S is present.
PP5V_S5_LDO = 5v
PP3V3_G3H = 3.3v
L7670 reads .09 on diode instead of .42 haven't managed to solve.

 

[2informaticos]

Overvoltage through Q7660 damaged something on the 5V_G3S power rail.
Inject 5V there and check with IR camera if any components gets few degrees more than the others connected to the same rail.
You may need to wait several minutes, hoping this may help.
Resistance to ground is not too low, dificult to find the culprit; unless something enters into thermal avalanche.

 

[TBFix]

Hi thanks for your help, only thing that stands out is around U2120 ,the 4 resistors feeding it get to 30c with 5v injected at L7670. Strange thing is boardview shows the ic but pdf file will not find it. Is there a 820-01521-A version of schematic?

 

[TBFix]

I found was what dragging down the diode reading for l7670 (U8110) replaced but now cycles between 50ma and 100ma 20v (stays at .50ma with battery) . Tried restore and revive dfu but they error out at the end with "gave up waiting for device to transition 0xFCA). Will continue to troubleshoot. Any ideas welcomed.

 

[2informaticos]

Inspect audio board/flex for corrosion.

 

[TBFix]

I made some progress. I changed u7650 now getting 100ma then goes to 900ma then cycles back down to 100ma . If I leave it then it starts charging the battery and goes to 2 amps. Another short somewhere ?.

Inspecting audio board now, again thanks for you input its greatly appreciated.