DV6000 (DV6809) Power problem.

[esgeroth]

I am attempting a repair on an HP DV6000 laptop with a power issue. The laptop is not getting power from the a/c. It will power on and run fine on battery until it runs out but still does not charge the battery.

The dc jack is not the problem, I have confirmed that there is power getting to the motherboard.

I have checked the mosfets in the power in area and I think they are ok.
There is an AO4430 next to the a/c in that measures in diode mode .484 from source to drain. The mosfet is open when measured from drain to source.

There is also a FDS6679 nearby that measures from drain to source as .145 and open when measured from source to drain.
I thought that value might be low so I pulled the mosfet and tested it by itself and it measures .465.

I next thought to check the max8724 chip.
There does not seem to be any power supplied to the dc in when the power is plugged in. There is power present to some of the other pins when the battery is connected.

I found a schematic for a similar board that has helped me understand where the power should be going: hp_dv6700_intel_quanta_at3.pdf

I'm not really sure where to look next. It looks like there is a power interruption somewhere but I can not find it. So I ask for someone who may know these boards better than I do, what should I do next?

[esgeroth]

Re: DV6000 (DV6809) Power problem.

I need to make a correction to the above. There is actually .6v supplied to the max 8724 DC IN pin. I assume there should be more.

[godin]

Re: DV6000 (DV6809) Power problem.

If you can get your head round the language these 2 docs will help. Learn how it works on a DV2000 schematic and cross reference to your AT3 and you should develop a really good understanding of the whole power theory.
Good luck

[esgeroth]

Re: DV6000 (DV6809) Power problem.

Ok, maybe someone can help me follow this schematic. I can follow the power for a little and then I get lost.
I have attached the page from the schematic detailing the power input and battery charging.
I can see that the power comes in at the top and and stops at VA and VAD on the schematic.
There is 0v at the max8724 ACIN, which means that it will not detect that the power cable is plugged in. I have traced that back and tested the resistors PR11, and PR12. Neither are open or shorted. Looks like those resistors should be getting power from VAD-1, but I don't know where this comes from. I don't see how to follow VAD to VAD-1.

[godin]

Re: DV6000 (DV6809) Power problem.

Look on the far right of the drawing in the blue oval

[esgeroth]

Re: DV6000 (DV6809) Power problem.

There is no VA or VAD within the blue oval. From the direction of the diodes it looks like that part of the circuit is getting power from VAD-1. It still doesn't show me how to trace the power from VAD to VAD-1.