00840 20V 0A PPBUS 13.1V

[grmacs]

No signs of liquid. Machine died for no known reason according to customer.

PP5v_S5 and PP3v3_s5 are present. Checked diode on all big coils and checked with IR for any heat on board. Tested on bench with only power cord plugged in. Doesn't start in SMC bypass.

PM_EN_5vS4 is not present. S5 Pwrgd is present. SMC_reset_L is 3V.

I'm unable to find what would trigger PM_EN_5VS4 or if something is missing between that and S5_PWRGD. I also checked diode mode of both battery SCL/SDA and they match at .429

 

[2informaticos]

You've forgot to specify exact PPBUS_G3H voltage (without battery).

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L, at same time.

 

[grmacs]

Was in the title: PPBUS_G3H is 13.1V without battery. I’ll report on the others tomorrow. Thanks!

 

[grmacs]

Yes. PM_PWRBTN drops from 3.3V to .3V when triggering SMC_ONFF_L

 

[grmacs]

PM_BATLOW was stuck low. Checked and near 0 in diode mode red to ground. When I pulled off shield on U2800 a bunch of caps and diodes moved near DCIN ports. I put everything back pulling parts from different board and thought everything was good. Plugged in and board started to try to start and pulling amperage but U2800 fried a hole near the center and dead short on PP3V3_TBT_X_S0. Don't know if it having heat to it finished it off or something else wrong. Not seeing anything out of sorts near the ports. short is gone after pulling U2800

 

[2informaticos]

Machine should boot without U2800, if U2890 is OK.

 

[grmacs]

Very much appreciate that tip. I wouldn't have guessed it would boot without U2800 considering how Apple is tying everything together before booting. Yes it does in fact boot without the U2800. SO hopefully replacing it will get me back in business. Thanks again!