HP G72 No Power

[BlueMidnight]

Hello everyone. I'm a little bit puzzled at the moment and was wondering if someone had any ideas.

I can follow the adapter voltage all the way to PQ52. PQ52 is off because ACOK# is at 5 Volts. That drew my attention to the ISL6251A . ACSET (pin 2) is at 0 V, so that explains it. But I don't understand why it's at 0 V. 18.5 V is right on the other side of PR235. PR235 and PR236 are fine.

I've tried replacing the ISL6251A (PU6) thinking there was an internal short of some kind, but that didn't change a thing.

1 (VDD) = 5 V
2 (ACSET) = 0 V with fluctuations as high as 0.4 V
3 (EN) = 1.13 V
22 (DCIN) = 18.5 V
23 (ACPRN) = 5 V

I checked all the nearby resistors and caps for shorts. No bad components were found.

[ktmmotocross]

Re: HP G72 No Power

check both sides of PR235 for resistance to ground and for voltage

[BlueMidnight]

Re: HP G72 No Power

check both sides of PR235 for resistance to ground and for voltage

On PR235 I get 18.5 on one side and "0 V with fluctuations as high as 0.4 V" on the other. With power disconnected, resistance on both sides is greater than zero.

[ktmmotocross]

Re: HP G72 No Power

maybe bad ic. as schematic says on the side to ic, ACSET must be 1.26V if vin is min 12V. it is done by resistor pr235 and pr236. check both if have good resistance.

[pecrie]

Re: HP G72 No Power

BlueMidnight ,

Did you manage to solve the issue ?