HP G62 Blinking power button

[John_F_L]

Hello everyone,

I have 3 HP G62 (mb: 615382-001 and 610160-001) all with the same problem.
The power button is blinking, I have the 3,3V and 5V if I press and keep the power button, but the 19V rail is not stable. It is going from 19V falling to 8-10 and again 19 and so on. I already tried to change the MAX8731AETI and the same thing happens.
Also if I remove the PJ1 or the PJ15, the 19V is stable, no up and down.
I haven't change the PU850 - PU11 (SN0608098) because I don't have a spare one (I don't believe that my problem is there because I have the 3,3V and 5V).
Also I have checked all the coils for short to ground, none of them is shorted.
Battery is dead, so I don't know if the laptop starts only with battery.
Any other thought would be great.

Edit:
after searching a little bit, I cleaned pj542 and until there I have stable 19V and 3.3V on PL11. I cannot find any short on the line after the PJ542.
Also another thing I saw is that on pin 11 where is supposed to be +V3.3S i measure 1.8V. I tried to find out if there is a problem with the +V3.3s but no luck.


Thank you.

[ktmmotocross]

Re: HP G62 Blinking power button

if u hve non stable VIN after start u must have short in some powerswitched rail.

post schematic

[John_F_L]

Re: HP G62 Blinking power button

i'm posting both the schematics of the two motherboards.

[ktmmotocross]

Re: HP G62 Blinking power button

check for short on all PJ jumps

[John_F_L]

Re: HP G62 Blinking power button

i checked for short but none of them had one.
Today I got another one that had a temp problem. I connected it to my power supply and saw the same thing. I said no way, so I got the customers psu and worked fine.
Then I tested the customers psu with those laptops I had the problem, the 2 worked fine, the third one ( 615382-001 ) I press the button but nothing happens. No fan spin, no light, nothing. The 19V are stabilized.
I'm thinking reflowing the chipset for start and if it works, I'll reball.

[John_F_L]

Re: HP G62 Blinking power button

I tried today these:
1. Change the bios chip with a new one.
2. Reflowed the Chipset to be sure before reballing.
3. Change CPU and Ram from a working one.
After all the changes, nothing happened again. I press the power button and it's not working. The only thing I have after the power button is the 5V rail for 5-6 seconds.

[ktmmotocross]

Re: HP G62 Blinking power button

u have power timing in schematic so go after that

[John_F_L]

Re: HP G62 Blinking power button

Hello again, I couldn't find what was the problem, I just gave it to the customer unrepaired.
Thank you for your answers.

[ala_borbe]

Re: HP G62 Blinking power button

try to convert to uma, it can be shorted vga chip or balls under vga

you have a thread here on forum