HP 4720s Laptop does not respond to the power button

[khaahk]

Re: HP 4720s Laptop does not respond to the power button

Lower left corner - seen worse working, think it shouldn't be cause for not working.
U90 should be near 2 coils L56 and L58, also near FETs U82.88,91,92, maybe opposite side of the board but close. From the internet pictures i presume it is on the opposite side of the coin cell region.

Small stupid question: have you tried removing the coin cell for 5 min?

[n3v3n]

Re: HP 4720s Laptop does not respond to the power button

I did remove battery, but it was less then 5 min.
Regarding U90 I'll do my best to find it today when kids go to sleep.

[4m0k]

Re: HP 4720s Laptop does not respond to the power button

Any luck with this one?
Got the same problem with 4720s - random shutdowns in BIOS or while loading OS.
My first thought was it's an overheating issue but after some fiddling around it seems more like a "faulty capacitor" kind of problem. Like a PSU with bad caps which, started from cold state, runs for a couple of minutes but then starts to shut down more and more often.

[alas3376]

Re: HP 4720s Laptop does not respond to the power button

i have the same issue with the same model of laptop

[ktmmotocross]

Re: HP 4720s Laptop does not respond to the power button

"started from cold state, runs for a couple of minutes but then starts to shut down more and more often."

sounds like a bad chipset IC