820-3662 Working fine on charger, battery detected and charging but won't run on battery - PP3V42_G3H looks OK

[senjoys]

Ok, cleared to do the repairs - but I'd still like to assess as much as I can before making anything hot. I want what's best for the board so if it has to be shipped to a specialist, so be it!

 

[2informaticos]

First of all, welcome to the forum!

If I correctly understood, you get correct 3V42_G3H with only battery (no charger connected)?
Machine turns of when you unplug Magsafe?

Does it make any attempt to turn on with battery alone?

Check for corrosion around U5110.
Be sure to get correct voltage at pins 1/3, only with battery.

 

[senjoys]

Thank you for the welcome and moreover for your reply!

With just the battery connected I get 3V42_G3H, I do also get 3V42_G3H with the Magsafe (and no battery) connected or any combination

Yes, the Mac turn off completely and instantly when the Magsafe is disconnected.

With just the battery connected the Mac makes no activity when power button pressed - not even a fan twitch.

Just checking U5110 now...

 

[senjoys]

It does look clean as does the surrounding - 3.42 on 1 and 3

 

[senjoys]

For ref, the other U5110 pins;
1 - 3.42V
2 - gnd
3 - 3.42V
4 - 2.75V
5 - 80mV
6 - 3.4V
7 - 3.41V
8 - 3.3V

 

[2informaticos]

"5 - 80mV"
Really bad, missing SMC_RESET_L.
Be sure R5127 is 0 ohm.
Change U5110, may have bad internal contacts.

 

[senjoys]

Ok, that's the most promising thing I've read all day

Setting that up now, will post results back here as soon as - Thank you!