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820-00165 Missing PM_SLP_S5_L, Brief Power.

S

SMMRepair

Member
Got this board in with very light liquid damage. A few burned resistors near the SMC and U5110 were replaced. Green/orange light and a fan spin for about 1 second, then off. No cycling. Checked SPI ROM, area looks good, but tested without chip in place (no fan cycling) and also with another SPI ROM just to see if it would affect anything, it didn't. Replaced original SPI ROM chip. Decided to reflow SMC since there was liquid nearby, and no change. Pulled SMC to make sure nothing ugly underneath, and it was really clean. While SMC was removed, I checked continuity of all BIOS lines and they're all good. Resistors all measure properly. Replaced SMC.

SMC_RESET_L is present (3.3v), PM_DSW_PWRGD is present (3.38v), as is everything up to PM_SLP_S5_L as far as I can tell. When charger is connected, fan spins briefly and VCORE/PM_SLP_S5_L both spike/pulse, but then to 0v and the board has no power again. Main rails present, no shorts. Everything after PM_SLP_S5_L missing.

Anything I can check before deciding the CPU is dead?
 
D

dukefawks

Administrator
It doesn't cycle which is unusual. Does CPU Vcore get voltage, 1 sec. should be long enough to get a reading. I would also inspect around SMC again for bad resistors/traces.
It is not true that anything after SPL_S5 is missing. If Vcore comes on then the whole power sequence already finished successfully.
 
S

SMMRepair

Member
Hey Duke, I meant that after the initial spike/fan, nothing after PM_SLP_S5_L is present (any longer). Sorry for confusion. It seems that after the fan turns on briefly, and then back off, I have everything before PM_SLP_S5_L steady (3v3/5v/1.05v sustains, etc). PM_SLP_S5_L is the first signal to be gone after the brief power-on.

As soon as charger is connected, VCORE spikes to 1.05v according to my scope.

I'll check around SMC again, but have checked very well and everything is in place and no visibly damages or ugly resistors.
 
S

SMMRepair

Member
OK, so you meant in the brief .5-1second of when the fan turns on. Yes, it seems I have all appropriate rails for a split second, but then nothing. I thought you were asking if pgood at R1962 was present at all times (it isn't), but yes, it is present in that split second when I first plug the charger in. Sorry for the confusion.
 
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