A1502 820-3476-A no power

I, have an A1502 820-3476-A that that doesn't power on.

It has no greenlight, no fan spin, and only puls 0.2A from bench PSU.

I don't have PPBUS_G3H (0V), but I don't think that is shorted (diode reading is 0.125 and 8Kohm of resistance to ground).

F7140 seams to be OK.

On L7130 I get 0.66V

On PPVBAT_G3H_CHGR_REG I get 0.123 on diode measurement

Can you help?
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Staff member
Don't you have original charger?
Did you even read the voltage delivered by original 60W charger?
Is marked on it.
Why the people like to always inject 20V with lab PSU on the Apple machines?
OK, understood.

I don't have an origibal charger. With 16.5V on lab PSU, I get 16.43V on PPDCIN_G3H and PPDCIN_G3H_ISOL
Afetr all, it is not ok, yet...

Now I have ower, but it is giving me 3 beeps. What can I check to try to figure out if thw problem is CPU ou RAM? Can it be anything else?


Staff member
This model isn't known for such issue.
You can try to reflow the RAMs, until make them dance a bit.