GTX480 short/vCore issue

[tony359]

Hi all,

I have a weird issue with a GTX480 I am repairing for fun.

Originally it would crash Windows when drivers were being installed. I checked with MATS and found a faulty RAM IC. I replaced it, MATS is happy but still the installation fails to install the driver - but no more BSOD.

While testing I found something weird.

What I think is the VCORE, is completely shorted. I read 0.4 Ohm to ground. I'm aware that low resistance is normal around a GPU but I don't think 0.4 is ok?

If I check the inductors and all the mosfets, they all read shorted to ground.

If I use the oscilloscope, I see the attached (vcore.PNG) but that might be because I am very close to the inductors - I believe I found the same signal at the back and it's smooth.

Do you think it's normal to read 0.4 Ohm on a vCore for a GPU??

Thank you!

[ktmmotocross]

Re: GTX480 short/vCore issue

yes

if gpu is shorted u dont have picture at all

[tony359]

Re: GTX480 short/vCore issue

Yeah that’s what I thought.
The card works. The issue with the driver seems to be windows 10 as drivers work totally fine in windows 7. I did some stress tests and they are all fine.

But 0.4ohm on GPU phases? Really?