820-3476 sometimes not starting


New member
Hi guys, a weird one here:p. Customer came in with dead macbook, replaced the battery, macbook runs. 2 days later client returns, dead again. I disassemble, test board with a good charger, fanspin.... Must be a badly connected keyboard cable? Put it back together, rebooetd about 20 times in a day. Left it overnight, dead in the morning. When press power, sometimes it showed the red battery sign. So me think bad U7000 or resistors? So I connect the charger, itboots again. It is charging the battery, all readings are OK. Turn off without charger. Press power, now it boots again without charger, all working! Checked the board, all looks clean, tried another keyboard but same story. Just now I connected the charger without battery, and also not booting. PPBUS is 12.9v, I have 3.3v but no 5v. It should turn on from the charger? I press power button, now it boots.

I dont know where to start :)


Staff member
Does it always start when connect charger, w/o battery?
Check if SMC_ONOFF_L is stable high w/ KB connected.
Also test if always good w/o RIO flex connected.
Be sure RTC signals are all high and stable.