820-3662 - Not entering S4 state PM_SLP_S5_L and SMC_S4_WAKERC_EN jumping voltage.

[dukefawks]

Power cycling. Is CPU Vcore cycling too?

 

[MUUK]

Yes it is PPVCC_S0_CPU jumps from 0 to 1.69v then repeats. A rabbit hole ?

 

[dukefawks]

There is hope, inspect board carefully for more corrosion. Was the connector cleaned/removed? May still have crap under it.

 

[MUUK]

Thanks Duke. Initially i cleaned and touched up the connector. After this did not change anything i removed the connector entirely. Looking at the pads for the connector they don't look burnt or missing.
Having another look round the board there is a dab of liquid on top of U7310 - but pins and area around look clean - this seems to deal with CPU_ISNS and is powered by PP5V_S0 so probably not important if not getting to S4 ? - i may just ultrasonic this and see if that does anything and report back.

 

[MUUK]

I spent a good hour checking over the board but did no spot any hints, as such I did US clean this board. I do now get quarter fan spin which repeats. Same voltage jumping on PP5V_S4. Any further thoughts before it goes to the bottom of the pile ?

 

[dukefawks]

Yeah, one drop of water near U7310 and it will have fucked the CPU as usual

 

[MUUK]

Ah, oh well. Thanks for your help it is greatly appreciated.