Help me diagnose HP DV6810us? No boot, no screen, no power.

JGAN

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Sep 9, 2011
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Hi everyone,
I have an HP Pavillion DV6810us, aka DV6700, aka DV6000. It has an AMD cpu and NVIDIA chipset. The problem is that it will not boot at all. No fan or hard drive spinning, no lights, no beeps, nothing.

I know that these laptops typically have overheating problems and the graphics card will need to be reflowed, but I don't think that's the problem because the laptop is not even powering up or POSTing. I did remove everything and try to turn it on without, but it's the same exact thing.

My main suspect is the PPM or VRM chips, as those are typical causes of this no power symptom. However, I suppose it could be a capacitor or driver on the mobo also. Also, the DC adapter works fine, and the charging ring and light turn on when plugged in.

On my laptop, the power mosfets are different than the ones in the link above. the FDS6679 is a 4856a, and the AO4407 is a 6679gm. I know I can go ahead and unsolder these and test them outside the circuit, but if I did that I might as well just put new ones on, and also, I don't want to risk doing a bad solder job and ruining the rest of the board.

So basically, is there a way to go about testing the board without unsoldering anything? I have a DMM with diode and capacitance functions and a block diagram/schematic available. I really don't want to replace the board because I want to be able to sell this computer for a new one and putting a new mobo in would be too expensive and not worth it.

Here is the schematic/block diagram; it was too big to upload here.

http://goo.gl/cRDGZ

Also, here are a couple shots of the mobo from the top and bottom.

http://img803.imageshack.us/img803/4092/hpdv810usmobotop.jpg <- top
http://img824.imageshack.us/img824/8461/hpdv810usmobobottom.jpg <- bottom

Any help would be greatly appreciated!

Thanks,
JGAN
 

JGAN

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Sep 9, 2011
42
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18,540
I would like to try to repair this - mostly just to say I can ;)

I have tested the coils/inductors and a bunch of mosfets. I think I will try to test the chipset next; maybe I just need to reflow?