Need to find where to read GPU voltage

[voltazze]

I am very new to reading laptop circuit schematics, which I find a bit confusing. I would appreciate if someone would help me to find the points where i can attach a multimeter to read the GPU voltage. Normally, under load, the GPU voltage should be at about 1.2v if that helps.

I have attached photos of schematics relevant to the GPU power circulatory to this post.

The full service manual/schematic can be found here: https://drive.google.com/file/d/0B10...ew?usp=sharing

[lezsimply]

Re: Need to find where to read GPU voltage

I think gpu voltage can be measured on coils L507 and L503.

[voltazze]

Re: Need to find where to read GPU voltage

I think gpu voltage can be measured on coils L507 and L503.

Thanks, i will test that out later

I am struggling to find where is the actual power output to the gpu. can you help me find it?

[voltazze]

Re: Need to find where to read GPU voltage

Any ideas how can i overvolt the gpu to about 1.35v?

[fzabkar]

Re: Need to find where to read GPU voltage

The GPU voltage is set by the potential divider consisting of R831, R813, R812, R811, R830. The REF voltage is 2.0V.

The three GPU voltage selections are achieved by bypassing R811 or 830 to ground via Q531 or Q532.

D0 = 0, D1 = 0
(1 - (43.2 / (43.2 + 36.5 + 15 + 15))) x 2 = 1.212V

D0 = 0, D1 = 1
(1 - (43.2 / (43.2 + 36.5 + 15))) x 2 = 1.088V

D0 = 1, D1 = 0
(1 - (43.2 / (43.2 + 36.5))) x 2 = 0.916V

If you replace R812 (zero ohm link) with a 22K resistor, then ...

D0 = 0, D1 = 0
(1 - (43.2 / (43.2 + 36.5 + 15 + 15 + 22))) x 2 = 1.344V

https://cdn.badcaps-static.com/pdfs/...7406beac84.pdf