820-3115-b Intermittent green light.

Possible liquid damage but has been ultrasonically cleaned before i took a look at it.

works normally when running on the battery
when the green light finally does come on it charges completely fine and operates normally.
when battery is connected. battery has to be removed and let sit before plugging power adapter in and actually getting green light.
here are some measurements
when green light is on 16.9v at pin 1 + 2 j6900

when no green light 1.6v and dropping until it powers back on at pin 1+2 j6900

38.6k to ground from pin 1 j6900

no beep on c6905
no beep on c7085
no beep on c7087

f6905 0
r7085 468k
r7005 20.3
****r7080 54k not 100k
r7081 62.6k
r7020 0
r7021 10
r7021 10
r7025 0
****r7086 207.4k not 332k
r7005 20.2
r7011 9.28k
r7010 29.83k
r7042 0
r7001 4.7
r7013 not present
r7012 1k
r7015 100k
r7016 3k
r7000 0
r7051 2.3
r7052 0
r7050 0
l7030 0
r7040 0
 

larossmann

Administrator
Staff member
When the green light disappears, will shorting pins 10 & 11 of U7000 bring PPBUS_G3H to 12.23 or no? I have a feeling there's some issue with Q7085.

1.7v is usually the magic number when there's a short circuit to ground.
 
Shorting pins 10&11 has no effect on PPBUS_G3H.
It also is slowly dropping in voltage until near zero, then green light re appears and board powers on.

Replaced q7085 and the issue is unchanged.
 
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