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Graphics card seems fried after a few weeks of working fine
November 24, 2011 11:52 PM   Subscribe

I installed a new video card and power supply in a new desktop computer, but the machine had problems (restarting occasionally for no obvious reason over a few weeks) and now the card seems dead. I need help figuring out what has gone wrong!

The machine is an HP Pavilion Elite H8-1010. I bought a new video card (radeon 6850) and power supply (Corsair TX650 V2) and installed them, after verifying that the machine was functional with the old ones. It's running Windows 7. I installed the drivers from the disk provided with the video card.

Things were fine for a few weeks, then I'd notice that the machine had restarted while I was not using it. I re-enabled the blue screen of death to make sure it was not crashing, loaded up speedfan to verify that it wasn't overheating, then installed Prime 95 and just let it sit, stress testing, for a few hours, and nothing happened.

Then today, it started restarting more and more. After four hours of use, it restarted. Use in this case can mean text based MUDs (yeah, yeah) or just sitting idle. Then after thirty more minutes of use, it restarted again. Then it at that point, the graphics seemed to cease to function and it would restart after a minute of loading windows. You can hear the windows startup sound, but the monitor claims there is no input from the graphics card. And that's the state it's in now.

I put the old card back in and it worked fine, for whatever that's worth.

I am at a loss. Is the new card just a dud? Is there some bad interaction between the card and the PSU? I am pretty good at fixing things if I know what is wrong, but I'm not really sure where to start with this one.

Snowflake details: These are both japanese components, but the machine is from America. The PSU claims it can take any AC input from 90~264V, so I didn't think that would be a problem. The machine is receiving 120V as input.
posted by ZeroDivides to Computers & Internet (9 answers total) 1 user marked this as a favorite
 
I put the old PSU back in just in case it was causing problems somehow, so now the machine is back to its original components. When I tried to turn it back on, it had the same problem as before -- the monitor says there is no signal. Tried different cables, using the HDMI socket and the DVI socket with no change. Grar.
posted by ZeroDivides at 1:31 AM on November 25, 2011


How hard/easy was it to seat the new card? On more than one occasion I've had a badly seated card short out against the case of a PC because it moved slightly over time.
posted by Lentrohamsanin at 6:05 AM on November 25, 2011


Restating the problem: machine worked fine with original components, and you wanted to upgrade the video card, which required a PSU upgrade as well? You replaced them and it worked ok for a while, but started rebooting and not starting. Now that it's not starting, you put the original stuff back in, and it's still not starting up?

Question: the way you worded this "I bought a new video card (radeon 6850) and power supply (Corsair TX650 V2) and installed them, after verifying that the machine was functional with the old ones," makes me wonder if this is a new machine to you. You got it from somewhere, or are upgrading it for someone? Are you sure it *worked* previously, as in would run reliably for an extended period, or is all you know that it would POST?

Regardless, unless you've managed to static-zap both video cards, it seems like a motherboard problem. Check the board for bulging capacitors. But my guess is that the PCIe connector might be no good. See if the video card will physically fit into one of the other slots- the PCIe spec says that it *should* function if it fits. It may complain, and for sure it won't function well, but you should get video as long as the first lane is connected.

This is a long shot, but I've seen it happen: a bad small capacitor near the PCIe connector. The board I saw it on had a bad cap near the onboard SATA connector, and caused it to not work right. The way I was able to identify it was that it was literally squealing. So, any funny high pitched noises coming from the motherboard?

(Does the motherboard have a built-in video connector? What does it do with no video card installed, running off that connector?)


(For reference, you are right that the input voltage shouldn't make any difference. Modern power supplies convert the input voltage up to many thousands of volts such that the 100v of difference between the inputs shouldn't make a difference.)
posted by gjc at 7:46 AM on November 25, 2011


Modern power supplies convert the input voltage up to many thousands of volts such that the 100v of difference between the inputs shouldn't make a difference.

Not thousands of volts. A few hundred volts. Specifically, the most common intermediate DC voltage for a power correction factor stage (PFC) is nominally 385 volts, with a maximum of 415 volts.

Because the PFC stage is a boost converter, the output voltage must be above the peak input voltage. For the worst case this assumes a maximum input of 264 volts AC (nominal 240 plus 10%) and then multiplied by 1.41 to give the AC peak of 372 volts. The DC output must be above this peak for a boost converter and the most commonly used output is nominally 385V. You don't want to go unnecessarily much above this required minimum voltage because the switches and capacitors get bigger and more expensive.

This 385 volt DC intermediate stage is then bucked down to provide the 3.3V, 5.0V and 12.0 V outputs to the motherboard.

But, yes, the power supply is tolerant to a wide range of AC input voltages due to the PFC boost converter. It takes anything from about 88 VAC to 265 VAC and converts it to 385 VDC. Not thousands.
posted by JackFlash at 11:23 AM on November 25, 2011


It sounds more than plausible you got a bad card.

I installed the drivers from the disk provided with the video card.

This is unlikely to be the cause of your problem, but you should get the latest drivers from ATI instead of bothering with the disk. This goes for just about any hardware these days, but especially video cards.

Also double-check to make sure all the necessary power is plugged into the video card. Lots of cards require extra power connectors.
posted by neckro23 at 3:45 PM on November 25, 2011


>> Lentrohamsanin: How hard/easy was it to seat the new card? On more than one occasion I've had a badly seated card short out against the case of a PC because it moved slightly over time.

The video card was pretty huge compared to the old one, but I was pretty firm in making sure it was seated, I think. That's a possibility to consider, though. (Ugh!)

>> gjc: Are you sure it *worked* previously, as in would run reliably for an extended period, or is all you know that it would POST?

Yeah, it's a new machine. I wanted to have something capable of handling the Star Wars beta with rather short notice.

>> gjc: (Does the motherboard have a built-in video connector? What does it do with no video card installed, running off that connector?)

After trying the old card, I took it out and tried the onboard video (the port helpfully covered by the mfg) and let it sit for a while with no trouble. Then I put the old card back in and tried it again, and the old card worked. It did manage a weekend of the star wars beta with no problems before all this started, with the new video card.

>> neckro23: Also double-check to make sure all the necessary power is plugged into the video card. Lots of cards require extra power connectors.

It did require extra power, which I had plugged in. I should know better about the drivers, grar.

Thanks for giving me some options to consider. If one of them pans out, I'll post an update.
posted by ZeroDivides at 7:24 PM on November 25, 2011


Okay, I was messing around and switching things out to try to figure out who is the culprit, and the new corsair PSU has totally stopped working. It fails the paperclip test now. So hopefully that is the problem.
posted by ZeroDivides at 2:11 AM on November 26, 2011


There are some known issues with some batches of the Radeon 6850. Here's a video and long forum thread documenting some of the problems. I was able to return mine to the manufacturer (Lexy Pacific in my case) for a replacement using their RMA process, though it meant being without a video card for 4-6 weeks. The replacement works beautifully.
posted by platinum at 1:43 PM on November 27, 2011


Just by way of update, I returned and replaced the PSU, and it has been running for a year or so now with no trouble. So the PSU was the culprit!
posted by ZeroDivides at 9:42 AM on November 24, 2012


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