No corrosion on board.
At the start there was 5V and 0.1A from charger.
One of the CD3215 had burn mark and then I found PPV3_UPC_XA_LDO was shorted to ground.
I replaced that IC, short gone and then I found other CD3215 got short as well on PPV3_UPC_xx_LDO.
At this stage PPBUS at F700 was 0.1V (no short) and I removed F7000
I replaced other three CD3215 a got 12.25V on F7000/1
F7000/2 in diode mode .338
And now when put back F7000 PPBUS got short spike to around 12V and then stays for a few seconds at around 3.9V and then again short spike to 12V and drop to 3.9V.
PPBUS in diode mode now got .369
Big coils near CPU got low resistance to ground but not shorted.
Any idea?
At the start there was 5V and 0.1A from charger.
One of the CD3215 had burn mark and then I found PPV3_UPC_XA_LDO was shorted to ground.
I replaced that IC, short gone and then I found other CD3215 got short as well on PPV3_UPC_xx_LDO.
At this stage PPBUS at F700 was 0.1V (no short) and I removed F7000
I replaced other three CD3215 a got 12.25V on F7000/1
F7000/2 in diode mode .338
And now when put back F7000 PPBUS got short spike to around 12V and then stays for a few seconds at around 3.9V and then again short spike to 12V and drop to 3.9V.
PPBUS in diode mode now got .369
Big coils near CPU got low resistance to ground but not shorted.
Any idea?