820-00165 Charges battery but will not run on battery. Only works when plugged in.

[bjf]

This board had some minor liquid-damage. Computer works fine and charges the battery fine but if you unplug it, it can't start or run on battery. PPBUS is staying fine at 8.4V on R7006. Q5500 circuit seems to be working normally compared to a good board. R7151 and R7152 are both fine. U7100 area is clean. I added pre-ultrasonic cleaning pictures. Not sure if this is an SMC communication issue or something else. It's obviously communicating enough to charge so I'm guessing that part is fine but I'm not sure what would cause this.

 

[2informaticos]

R7006 is the first suspect here...

Did you try known good working battery?
You can also test its battery in other machine.

Post Q7155 voltages with battery only.

 

[bjf]

Yes, R7006 is fine. Voltage getting through fine. It does have 3V42 on battery. To be sure I swapped R7006. No change.

Tried with working good battery. No change. I have a test board too. Battery works fine with that one.

Q7155
1-3: 8.4V
4: .875V
5: 8.4V

 

[2informaticos]

Post SMC_PBUS_VSENSE on battery only.
What says OSX about battery?

 

[bjf]

SMC_PBUS_VSENSE is at 0V, same as a good board. Diode mode on SMC_PBUS_VSENSE is .711, same as my good board. If you look in the pictures though, this was one of the few areas that was hit by the spill. Slight corrosion. R5503 and R5504 are measuring fine though.

OSX sees the battery normally. Charges fine. Condition is Normal.

 

[2informaticos]

Post U5110 voltages with battery only, no charger.

 

[bjf]

Ok, it looks like you've found the problem. Not sure what's causing it though. It has 3.3V on SMC_RESET_L while plugged in but it drops to .184V with battery-only. Other than that, all the values on U5110 are the same as a good board. Same results testing with other good battery.

U5110 (Battery-Only)
1: 3.4V
2: GND
3: 3.4V
4: 2.7V
5: .184V
6: 3.3V
7: 3.4V
8: 3.3V

 

[bjf]

Replacing R5100 made no difference, still at .184V. Replacing R7100 raised SMC_RESET_L to .6V.

 

[2informaticos]

Remove R7100 and check if SMC_RESET_L goes high.
If yes, solder back R7100 and change U7100.
Also you can remove J6100, if had corrosion close; not needed normally.

 

[bjf]

Done. Bad ISL. Thanks for getting me there.