820-3115 no battery detect. won't turn on without charger.

[mooserov]

I get a 0.53 v diode mode reading on r5280 and r5281, so they're not shorted to ground. I get 12.56v on ppbus_g3h with the battery unplugged. Tried known good battery.
3.17 ohms between pins 17 and 18 on U7000
20.28 ohms between pins 27 and 28.

when I connect the battery PPbus_G3h will read 12.56v for a few seconds, then drop to 11.6v for a few seconds, then repeat.

This one has me stumped.

 

[dukefawks]

Is the battery indicator working? It kind of sounds like just a dead battery.

 

[mooserov]

Battery indicator blinks one led on both batteries. No orange light on charger with either battery.

 

[mooserov]

Once it boots, it will run off the battery. doesn't die when unplugged.

 

[mooserov]

different board charges the battery ok, Orange light, and the battery indicator shows full charge.

 

[dukefawks]

How is the battery recognized in OSX? Charge cycles and charge capacity correctly reported? Any history of liquid damage?

 

[mooserov]

x through battery, shows not installed, 0 cycles. Had a liquid spill reported but no visible corrosion.

 

[dukefawks]

So battery is not recognized. I don't really see how you could get 12.56V on PPBUS then. Disconnect battery indicator to rule out that is messing with the data bus. After that it could be the ISL or SMC

 

[mooserov]

it's the SMC, can't swap it now.