HP 6830s no power, orange light blinking

[Kuhanzzi]

Hi,

I am beginner in motherboard repairs, and I am troubleshooting a laptop which suddenly stopped working.
When battery or charger is connected, charging port light up as blue and orange light starts blinking. Power button does nothing.

I disassembled laptop, and measured all power rails and everything seems fine.
Then I located this problem to LM393 "Low Offset Voltage
Dual Comparator".

When I touch pin 3 on LM393 (or anything it is connected direclty, see circled points in photo) with anything conductive (probe, tweezers, finger, screwdriver (plastic has no effect)), voltage on pin 3 rises from 2,27V to 2,33V after i touch it, blinking stops and then i can boot laptop.

But after shutting it down problem persists.

I cannot figure out why this happens




Should I replace LM393 (U4)? Could it be that simple?

[mcplslg123]

Re: HP 6830s no power, orange light blinking

Yes could be LM393 but i doubt resistor connected to pin3(the other end of this resistor is connected to pin1). Either the resistor it self is bad or there is damged track. inspect it carefully to find out.

[nassimhamdi]

Re: HP 6830s no power, orange light blinking

what happen?

[Duranitron]

Re: HP 6830s no power, orange light blinking

just replaced the LM393 and finger crossed guys...