MacBook Pro 820-00239 not turning on

[nadavt]

Hi all,

I got a MacBook Pro A1706 (820-00239) with no liquid damage, just suddenly stopped working and is not turning on. Before sending it to a local repair shop, I saw there was a short on PPBUS_G3H but couldn't identify the problem.

Machine was back last week from the shop, with a fixed PPBUS_G3H (no short, correct voltage) but said they couldn't fix it because the "CPU is probably dead".

After checking it again myself, I'm not sure how they've reached their conclusion since all S3 rails are missing.

So, to conclude:
* PPBUS_G3H, PPBUS_PMIC are present and good
* All S4 rails are present and good
* All S3 rails are 0 volts, no short to ground

Will appreciate any lead...
Thanks!
Nadav

[piernov]

Re: MacBook Pro 820-00239 not turning on

It's unusual to have all S4 rails and no S3 rails, double check it's indeed what's happening, and check if you get any S0 rail as well. What's the current consumption of the machine (without battery)?

Check PM_SLP_S5_L, PM_SLP_S4_L, PM_SLP_S3_L.

[nadavt]

Re: MacBook Pro 820-00239 not turning on

Will re-verify today all rails.
Still waiting for my USB-C amp meter to arrive, will post results as soon as I get it.

Thanks!

[nadavt]

Re: MacBook Pro 820-00239 not turning on

Measured some voltages now:

PPBUS_G3H: 13.05v
PP3V3_G3H: 3.35v

PP5V_S5: 5.12v
PP3V3_S5: 3.34v

PP1V8_S4: 1.79v
PP3V3_S4: 3.34v
PP5V_S4: 5.12v

PP1V0_S3: 0v
PP1V2_S3: 0v
PP1V8_S3: 0v

PP1V8_S0: 0.015v
PP3V3_S0: 3.34v
PP5V_S0: 5.14v

SMC_PM_G2_EN: 3.34v

PM_SLP_S5_L: 3.34v
PM_SLP_S4_L: 3.33v
PM_SLP_S3_L: 3.33v

* Still missing all S3 rails but some of the S0 rails are present
* Just noticed that I got the board back from the shop with a missing U7900
* Nothing gets hot on the board, even after it was plugged for 20 mins or so

[piernov]

Re: MacBook Pro 820-00239 not turning on

U7900 missing can definitely explain why you're not getting PP1V2_S3… Maybe the reason why you're not getting PP1V8_S3 either.

Athough if U7900 was removed, maybe it means there was an issue with PP1V2_S3, which could have damaged RAM and/or CPU itself.

[nadavt]

Re: MacBook Pro 820-00239 not turning on

Thanks for all your help!
I've order a donor board and will try to replace the missing U7900 and see if it makes any difference.