820-3437

[Kyle93]

Arrived with only liquid damage on pins 23&24 of U7100. Replaced U7100 and repaired traces from pin 23&24 but still 0 short to ground diode on PPBUS_G3H. Board draws 3.32V from power supply with 0 amp draw

Does this sound fixable?

 

[2informaticos]

Remove F7140 and check where the short remains.
If is on system side (pad 2), check if you get the exact same ohm (not diode mode) value on any big coil.

 

[Kyle93]

C7584 and C7374 were shorted. Replaced and board turns on and chimes but only on a/c adapter. If battery is plugged in theres no power.

What to check next?

 

[2informaticos]

Do you get 3V42_G3H on battery alone?
Ay least some voltage on PPBUS_G2H?

 

[Kyle93]

3v42_g3h 3.42V

PPBUS_G3H 6.47v

 

[2informaticos]

"chimes but only on a/c adapter. If battery is plugged in theres no power "
Do you mean board doesn't start at all with both charger and battery connected?
Does it start on battery alone?

 

[Kyle93]

Yes board does not turn on with both charger and battery connected. The fan will only spin a few seconds. Same goes for battery alone.

Board fully boots if a/c adapter is plugged in with no battery

 

[2informaticos]

Do you get amber light on Magsafe?

Check if battery is charging.
You don't need to turn on the board to check that...

 

[Kyle93]

No amber light or charging while battery is plugged in.

 

[2informaticos]

Amber light MUST be on without battery connected too.
Fix this problem first.

Did you try another LIO board/flex?
Check continuity for SYS_ONEWIRE list between MLB and LIO, with flex connected.
Inspect J9500 pins for corrosion.

For the future, describe exact the state of a board.
We cannot properly help, if not.

 

[Kyle93]

Amber light IS on without battery. Light does not come on at all when battery is connected.

Yes tried known good LIO board/flex

No corrosion on J9500

 

[2informaticos]

So Magsafe light goes off completely when you connect battery???
Did you try original Magsafe 2 charger?

 

[Kyle93]

yes and yes

 

[2informaticos]

Post voltage and diode mode to ground at SCL/SDA lines of battery bus.
Did you try known good working battery?