3115-B, dim green light on magsafe + DCIN rails pumping?

[JohnB8812]

Known good DC in board and 85 watt magsafe 1? Resistance to ground on PP3v42?

 

[Hardwood T/S]

Yes charger is known good, I've been using a 60w since it's a 13" board, but 85w returns same results. Tried multiple DC-in boards, PP3v42 has .310v drop in diode mode to ground, 1.655kohms in resistance.

 

[2informaticos]

Possibly leakage on the input stage.
Original charger detects it and gets blocked.
First check for short at CHGR_ACIN.
Also be sure both R7010/11 are OK.

Post exact value for R7080/81 and R7085/86; measured onboard, ohm scale.
Also post diode mode to ground at R7020, L6995 and C6990.

 

[Hardwood T/S]

While looking at R7080/81 I discovered R6905/R6990 were completely missing from the board maybe the guy before was using this board for parts, not sure. Either way, after replacing I now have stable DCIN rails, 3V42 and PPBUS_G3H are 3.44v and 12.56v respectively. The resistors you mentioned all returned normal values, plus current sensing is fine as well.
ONEWIRE and ADAPTER_SENSE are ~1.49v. No shorts on those lines. U6900/01 look fine, should try replacing anyway? Already replaced ISL earlier no change.

 

[2informaticos]

Post all voltages for U6900/01.

 

[Hardwood T/S]

U6900
(1)SMC_BC_ACOK_VCC 2.00v
(4)SYS_ONEWIRE 2.00v
(5)ADAPTER_SENSE 2.00v

U6901
(1,2)SMC_BC_ACOK 3.27v
(4)SMC_BC_ACOK_VCC 2.00v
(5)PP3V42_G3H 3.44v

Voltage went from 1.47v to 2.00v on the ONEWIRE lines since last time but still low.

 

[2informaticos]

"SMC_BC_ACOK_VCC 2.00v"
Replace U6901.

 

[Hardwood T/S]

Replaced it, works now thanks a bunch. Why does ACOK_VCC being 2.00v conclude U6901 being bad and not U6900?

 

[2informaticos]

U6901 generates that voltage, from 3V42; enabled by SMC_BC_ACOK.
If U6900 sinks too much current, it should drop more...