Help - PSUs keep blowing !

[Nomgle]

So, this is a weird one !!
I've been running a Gigabye GA-P35C-DS3R with an Intel Q6600 QuadCore chip and 4GB of Corsair XMS DDR2, with an OCZ StealthXStream 600w PSU and a nVidia 8800GT for the past year or so. No problems.

A month ago I bought myself a Palit 1GB Radeon HD4870 - http://www.palit.biz/main/vgapro.php?id=969 - comes complete with a custom dual-fan cooler as you can see in the pics.
I fired up Left4Dead, played for an hour, and suddenly my PC clicked off and the PSU puffed out a cloud of burnt smoke from the back. I could then power up (the fans would spin, so I guess at least some of the 12v rails survived), but it wouldn't POST (not that I expected it to, with a toasted PSU ).

So, I swapped out the PSU for a FSP 700W FSP700-80GLN (the specs of which matched the 600w OCZ exactly, so I suspect it may have had the same insides...). This one lasted an hour, before exactly the same thing happened - again I was playing Left4Dead at the time. Doh.

At this point, there were two scenarios. Either the new video card was breaking my PSUs, or, neither PSU was upto the job and I simply needed a bigger unit.
I chose the second option, and put in a Corsair TX 750w - with a single massive 12V rail. I figured that would be impossible to blow.
It worked fine for over a week, including a six-hour session of Crysis and a bit of Left4Dead.

...and then tonight, it puffed out the magic smoke during Left4Dead exactly like the other two ! That's three PSUs in a month, all after I installed the HD4870. I've got four Hard Drives and a few case fans, but nothing crazy - all three PSUs should have been more than capable of driving my PC.

I'm at a bit of a loss now. Could it be the 4870 ? It's my understanding that decent PSUs have protection against short-circuits etc. and a simple short wouldn't cause them to blow (ruling out a dodgy case-fan or similar) ?

I've read this thread with interest - http://forums.techpowerup.com/showthread.php?t=66763 - it seems to suggest that the VRMs can pull massive ampage if they aren't cooling properly ... could my card have this problem, and hence kill PSUs ?

[erocker]

Check the VRM temperatures using GPU-Z. Do you have the power supply plugged into a UPS or surge protector?

[spearman914]

Seems like it's the HD4870. To surely figure out, puff back in ur old GPU and test again. And what driver's u using or overheating?

[Nomgle]

I do have a surge-protector - but I think I can rule out dodgy mains power. We have generally clean power here in the UK, and I've had zero problems with the rest of my electronic kit.

I'll have to grab a fourth (!) PSU tomorrow before I can do anything else. Unfortunately I sold on my old nVidia card, so I can't put it back in to test.

[Woody112]

+1 for checking the VRM temps.

[Nomgle]

What should I use to load-up the card when I take the reading ? I'm gonna have to hope the temps max out pretty quickly ... it will be rather expensive if it fries the fourth PSU while I'm diagnosing

[intel igent]

W1zz's atitool work's great!

i'd check and make shure the card itself isn't touching a cap or similar....

good luck!

[lemonadesoda]

Originally Posted by Nomgle

I do have a surge-protector - but I think I can rule out dodgy mains power. We have generally clean power here in the UK, and I've had zero problems with the rest of my electronic kit.

UK power is about as good as it gets in the World except Germany and Switzerland which are even better.

HOWEVER, you could have a bad supply. Not "surges" but drop out or noisey line. Bad wiring. How old is the house? Where is your room. Check the wall socket. How is the mains ring configured in your house. Ask your Electricity supplier to check your supply.

OR. You have a short somewhere in your case. Intermittant. Kick the box, brief short, PSU survives... but only a certain amount of times.

Rebuild the machine. Dont just swap the PSU. Check all cables are good, check standoffs are clear of shorts.

[Polarman]

We rarely have any power issues here but even so, i always have my system plugged into a good UPS.

[Nomgle]

Grabbed a second 700W FSP700-80GLN (er, the warranty replacement for the first one !), so I'll have a fiddle around tonight when I get home.

This is what puzzles me the most : Modern PSUs have protection against shorts, overvolting, overloading, etc. etc. - if anything bad happens, they just switch off. I'm struggling to understand what could actually be blowing the PSUs when they're under load - they surely should just be switching off ?

...which makes me think about what lemonadesoda says above - maybe the PSUs are dying because of some issue with their input, rather than what the PC is doing with their output. I do actually have about a gazillion devices all plugged into the same double wall-socket...

[ste2425]

try it in a different room i no my house has an old set of sockets and a new set with it all rewired, my parents couldnt afford to do the whole house:P if i put my rig in an old it flicks the switch in the control box thing under my stairs mabye its the same thing for u

[crazy pyro]

You may well be overpowering the single wall socket which gives the PSU a brainfart, unplug everything else except for the monitor, if it still blows well, then you're screwed, IE wait for someone else to come up with a different suggestion. Try buying a really cheap graphics card just for fault testing perhaps?

It has to be the card. Look at my specs, and with aggresive overclocking my HX520W skips along just fine.

[Nomgle]

As a slight aside - would the use of a UPS instantly rule out all mains-related issues ?
If that is the case, then I could always connect one up. If it then blew a fourth PSU I'd know it was definitely something within my machine, rather than a power issue.

[Nomgle]

Ladies and gentlemen, the problem is solved !

I've just taken these two photos of the chips on the back of the card...




I'll RMA the card tomorrow. Hopefully the replacement won't have the same fault !!!!

Nice spot . . . Did you RMA each power supply as well?

[crazy pyro]

Good job on finding that, at least you ain't gonna need anymore PSUs for that one card... I'll have to make sure to check this on my card cheers mate.

[Nomgle]

Originally Posted by kyle2020

Nice spot . . . Did you RMA each power supply as well?

Yes, they were all still within their warranty periods. Though it cost me over 20 quid to ship the OCZ unit to their RMA centre in Holland

[Gam'ster]

Nice one finding that one, Hope the next one is better for you

Edit: ocz rma is pretty good... well for ram anyway but it all goes to the same place in holland, Also try and claim atleast your rma cost back from palit/amd.