820-00239 Won't power on, no liquid damage

DannyRinc

New member
Hey all,

Same thing a few people have had here. No liquid damage, customer says he took it to the beach and it wouldnt power on after a while. Checked inside and all i could find was a bit of dust, literally no signs of liquid damage.

After doing a bit of research I tracked down RTC_RESET_L as a possible culprit. It stays at a stead .3v. So in turn, pp3v0_g3h is at .3v. Does that mean my SMC is shot? Or possibly the CPU? If I leave it plugged in, every once in a while it will miraculously turn on. PP3v3_s5 is present, no SLP_SUS signal, so no 3v3_sus, and nothing higher after that.

Anything helps.
 

DannyRinc

New member
Yes. It's dead 90% of the time, but randomly if left on the charger it will turn on. I'm guessing bad cap along 3v0_g3h, but just looking for help. Backing up data right now since it's on before I do anything.
 

2informaticos

Administrator
Staff member
So only 3V0_G3H fails sometime?
R7020 and F7000 have always correct voltage, as 3V3_G3H too?

3V0_G3H is generated by U7800.
Check its area for corrosion.
Put good flux and reflow it.
 

DannyRinc

New member
Yeah only 3v0_g3h fails sometimes, R7020 and F7000 are always correct, as well as 3v3_g3h.
I checked U7800 for ANY trace of ANYTHING and it's completely clean. It's either correct or at .3v, but a steady .3v. I'll try reflow first, then probably track down bad caps if possible.
It stays on as long as I don't turn it off, so my guess it's a little cap just charges up eventually and allows 3v0_g3h to work at SOME point.
 
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