Low voltage on 3V42 line
I have a 820-2327 logic board fault which occurred in odd circumstances.
The laptop was working OK and I had powered it off (I thought I had) and was beside me while I was doing something else. I then became aware of the laptop fan running at high speed. The fan could only be stopped by removing the battery. Replacing the battery resulted in the fan either starting immediately or random running on and off.
The fault has progressed to the fan not running when the battery is connected (which is good as it should not be running when switched off). However the laptop will not boot and there is no green light when the charger is connected.
On further investigation the PP3V42_G3H measures less than 1v. Would explain the lack of green light on charger.
The PP3V42_G3H point measures 4.8ohm to ground. On a working board is 65K.
So something is low resistance on the 3.42v line.
Looking around the U6990 area I am hoping that C6999 on the line to ground is the culprit, although not yet had a chance to remove it to check. Also there is so much else on that line that could cause a low resistance.
My question has anyone seen a similar fault (fan running when powered off).
Also anyone have any ideas on the low 3V42 on where the next best area to check is.
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