macbook air Logic Board 820-3437-B FA turning on issue

[mobajer]

Hello, I have Logic Board 820-3437 board, which looks like new, no water damage. But sometimes refuses to turn on. But if turned, fully works. Thanks for advices.

 

[dukefawks]

Disconnected everything and just connected power? Checked PPBUS?

 

[mobajer]

everything disconnected, only charger, green light goes to orange and cooler don't start spinning. PPBUS_G3H is 8.6v, SMC_ONOFF_L is 3.4v. short to ground SMC_ONOFF_L but nothing happens.

 

[dukefawks]

If there is no liquid present then this one is going to suck. Sometimes there is corrosion around U1900 and the traces to Y1905. Intermittent issue are pretty hopeless

 

[mobajer]

could we discuss what voltages should be present to get MacBook turned on?

 

[dukefawks]

What good will that do? It turns on sometimes so finding such an intermittent issue is a nightmare. I gave you something to check. If that is ok then it can be anything and probably going to be a no fix.

 

[mobajer]

OK, throw this away.

have 820-00165 no water, clean as new. battery chargers, but no way to turn it on. if connect only charger green light changes to orange and thats it.

PPBUS_G3H 8.6v

SMC_ONOFF_L 3.4v

what voltages should I check next? what further steps. thank you

 

[JohnB8812]

Try connecting a known good battery and see if it powers on and stays on. If not, then trash this.

 

[JohnB8812]

Actually completely disregard my comment thought this was a 00165. I'm with Duke this is a time waster.