Testing killer video cards

[pentium]

So someone gave me two really nice EVGA 7800GTX cards but I was informed that both were "dead". (one of them supposedly killed a PSU on a test bench and both of them have the smell of PCB's) He has no knowledge on where they were before him but both came into a recycling shop a few months apart. There are too many variables on that one card which supposedly blew up a PSU (what was it rated for? Did the motherboard die too? etc.) and on both of them the smell of PCB's (cheap chinese stuff reeks of this stench) could be anything. It could even be completely normal.
The only real way to confirm if they work is to test them but I only have a single motherboard with PCI express and only one PSU that has the PCIe connector. If these cards, or one of them, is indeed bad. It will potentially kill one of my good systems and I can't afford to replace it.
Is ther a way for me to test the card without plugging it into anything? Use a DMM?

[Wizard]

Re: Testing killer video cards

If you have disposable board and PSU, if not, take a pass. Not worth your time if you need your board to live for long time.

Plus, reeky cards is very suspect.

Cheers, Wizard

[370forlife]

Re: Testing killer video cards

I would hold onto them if you can get them for free until you get a "disposable" board.

Only way they could really kill a psu is if it was a cheap psu with no OPP and it was overrated. If you have a decent psu with Short protection and Over Power protection the psu should be fine.

[PCBONEZ]

Re: Testing killer video cards

Look up the pin-out for PCI-E slots then check all the power pins for grounds.
You will have to check to all the grounds for each power pin because the common point [electrically] for the grounds is more likely on the motherboard than the card.
[Meaning some of the grounds may not be connected together unless it's in a motherboard.]

Also on EVGA look for Sacon FZ caps.
.

[NxB]

Re: Testing killer video cards

Check for shorted mosfets and regulators, etc

After this and the above the card should be "safe".

[Player2]

Re: Testing killer video cards

Check for shorted mosfets and regulators, etc

After this and the above the card should be "safe".

I concur. I've fixed a couple 7800 GTX's that had a slew of bad MOSFETs, although none of them took out my power supply. When tested with the PCI-E power connector plugged in, the machine would not come on (guessing the PSU went into protect). However, when I disconnected the PCI-E power cable it would POST and then give an error message. One word of advice, if you do end up replacing the MOSFETs, make sure you reattach the heatsink before testing! I made the mistake once of excitedly popping the card in and powering up and forgot the heatsink... the computer barely had time to boot into Windows when I smelled solder and a half second later it shut off.

[seanc]

Re: Testing killer video cards

Player2, any suggestions on which mosfets go bad?

I thought I had a shorted cap, but it was actually fine (replaced anyway).

I have found a D408 transistor/mosfet hiding under the heatsink which seems to be open, I will scour the pile of old motherboards with bad caps I have to see if any have some I can pull.

[seanc]

Re: Testing killer video cards

Hmm, well I replaced my D408. I tested it with the used pulls I got and it tested the same, put another one on anyway.

Powered a machine up with the XFX 7800GTX and the PCI-E connector unplugged, Q522 on the back of the card just turned into a fireball.

Can anyone ID it for me?

[seanc]

Re: Testing killer video cards

I've discovered that by holding the card at an angle in the correct light, it's an SP8J5.
Mosfet was too dark to read before it fried itself, it's obviously been hot, the markings just catch the light.

I can get these from Digikey, might try and find somewhere closer, shipping from the US isn't cheap.