Odd PSU problem

[Rys]

Last weekend I was using my PC in the morning, turned it off to go do something, and then came back to it later to find it wouldn't start. Pushing the power button forced a flicker of life where the fans would attempt to start spinning, but after a split second it was dead again.

So I took the PSU out (Tagan BZ800 modular) and tried it on its own, and it exhibited the same issue. Oh well, time for an RMA then. Fast forward to today and I've got the time to start the RMA process with the online store I bought it from. It's over a year old, so they don't want to know, but you can dispute that with them (the supply has a 3 year warranty which I'd like to take up with them first, rather than Tagan) if you can supply some details like the serial number.

I come through to my office to get the SN, and on a whim I decide to test it again just to make sure.....and it starts fine on its own. I try again just to make sure I'm not dreaming, and it starts again. The upshot is it's back in my PC and I'm typing this post from it now, after some new graphics drivers (downgrade to a 4870, after selling my 5870 thinking it was as good a time as any if my PC was dead, with GTX 4xx round the corner).

Anyone got any ideas what it could have been? My PC's been fine since I upgraded to i7, and then the 5870, and the PSU itself has been fine since GTX 280 launch day, when I bought it alongside one of those.

 

[Bouncing Zabaglione Bros.]

It's on the way out. It might be fine for weeks, then you'll turn it on one morning and it will be dead again. If I had to guess I'd say a cracked/cold solder joint, or a capacitor expiring.

I've had the same experience with a couple of PSUs that eventually failed. They had occasional failure on boot like yours, and then would work fine later, before finally getting to the point where they were just dead.

 

[Mize]

BZB is right. It will likely fail again. Did it buzz at all before it died the first time? That's typical of a cap dying. If not, cold solder joint. Was there anything particularly different about room temps the day it died or came back to life? Do you leave it running 24/7 and, if so, how long has it been up and running now?

 

[Rys]

Didn't hear a buzz before it died, and I didn't have the heating on in my office that morning (that I can remember anyway), so the usual ~18C ambient in here. Don't leave it running 24/7 (although I used to before I moved), and it's been up and running for over an hour now without issues.

I best budget for a new one sooner rather than later, by the sounds of it.

 

[Mize]

Yep. PSUs don't "heal thyselves" so something's bad on it. I'd get a backup and be ready to RMA that one.

 

[Grall]

Btw, why sell a 5870 to trade in for a 4x0? Preliminary benchmars point in a direction that the wisdom of such a trade would be of dubious value in most situations except for a few corner cases, particulary when factors such as price, power, heat and possibly noise are also weighed in.

 

[V3]

I had this problem before too. Like others said, the PSU is on the way out. Mine started intermittent, PC would turn off unexpectedly and sometimes would turn on afterward sometimes not, but next day it would turn on again. After one month, it died completely. I got it replaced under warranty. Don't know what's wrong with it though. Loose connection perhaps ?

 

[ShaidarHaran]

Btw, why sell a 5870 to trade in for a 4x0? Preliminary benchmars point in a direction that the wisdom of such a trade would be of dubious value in most situations except for a few corner cases, particulary when factors such as price, power, heat and possibly noise are also weighed in.

If nothing else I'm sure Rys is interested in GF100 because of it's architecture. Where the performance stands remains to be seen, but I have a feeling Rys isn't as pessimistic as prevailing "wisdom".

 

[stevem]

Rys, do the RMA. If you're handy with a soldering iron & have a multimeter, pop the cover & check for obvious cap failure. You'll need an ESR meter for a proper cap test. Check that the output mosfets/diodes are secured tight on the PCB/heatsinks if fastened with screws/threads (& don't have locktite). Reflowing solder to the secondary mosfets isn't a bad idea either. Or, RMA...

If nothing else I'm sure Rys is interested in GF100 because of it's architecture.

Aren't we all?

 

[Mize]

Rys, unless you've done PSU (or CRT) work before I wouldn't go probing around inside. Those caps can bite pretty hard for quite a while after power is disconnected.

 

[Grall]

If nothing else I'm sure Rys is interested in GF100 because of it's architecture.

Aren't we all? The pre-presentations of Fermi I've read, mostly over at Anandtech, makes Fermi the most interesting GPU architecture ever IMO. The fast thread switching, ECC protection throughout, improved coverage sample texturing and antialiasing, improved multisample AA, and so on and on. Fermi has tons of very cool stuff poured into it. Doesn't neccessarily mean I'd like to own one though if the first physical implementation of it turns out to be a bit of a lemon...

Those caps can bite pretty hard for quite a while after power is disconnected.

If you pull the wall socket plug and then push the ATX power button, surely the caps would discharge then?

 

[Mize]

Maybe, but in college I built and sold PCs (way back in the 286 days) and our repair tech would get bit by caps days later...also, where's the charge going to go if you're not connected to ground?

 

[Rys]

I'm not terribly keen to open it up to see what's gone wrong. Will soldier on with it until my RMA is granted and I can send it back, or they decline it and I go get a new one.

As for the 5870, I had the 4870 lying around after it came back (a friend was borrowing) and it turns out it's the fastest spare I've got, so I threw it in. And yeah, while I might be a bit more bullish than most when it comes to real-world 4x0 perf, outright speed isn't what's going to make me buy one.

 

[digitalwanderer]

Yep. PSUs don't "heal thyselves" so something's bad on it. I'd get a backup and be ready to RMA that one.

Agreed and seconded, count it as on its last legs.

 

[Grall]

I like Enermax PSUs myself.

Mine is the 1050W Revolution 85+, and with a 3.5GHz i7 920 and 2x 4890s all going full blast the PSU fan is only generating the most mild of breezes, and the air coming out of it barely feels any warmer than the surroundings. It's crazy how efficient this PSU is.

With the components in my PC, I'm hitting roughly the magic spot where efficiency peaks, meaning ~90% in my case. It's an incredible difference compared to my older Dell XPS 720, where the 92mm fan almost roars at full load, and the grille at the back belches hot, hot air.

 

[Bouncing Zabaglione Bros.]

I like Enermax PSUs myself.

I used to like Enermax, but I've had two of them expire (one in my machine and one in a friend's build) and each was less than three years old and they weren't cheap to buy. Now Corsair is my PSU of choice.

 

[Grall]

Corsair isn't a manufacturer of PSUs though, they jsut buy units from various other OEMs and put their own name on it. Corsair's good name nonwithstanding, wether the unit really is any damn good or not is basically a crapshoot.

 

[Bouncing Zabaglione Bros.]

Corsair isn't a manufacturer of PSUs though, they jsut buy units from various other OEMs and put their own name on it. Corsair's good name nonwithstanding, wether the unit really is any damn good or not is basically a crapshoot.

Well I presume Corsair have some pretty high quality standards for what they sell, because as you say, it's their name and good reputation on the line. They certainly get good reviews and have a good rep, and the TX750 I have is their mid-range product, and it's the best PSU I've ever used.

Enermax on the other hand have let me down a couple of times, and certainly if you do a bit of searching, there are a lot of people who have had issues with Enermax. YMMV.

 

[Npl]

Well I presume Corsair have some pretty high quality standards for what they sell, because as you say, it's their name and good reputation on the line. They certainly get good reviews and have a good rep, and the TX750 I have is their mid-range product, and it's the best PSU I've ever used.

Supposedly they have good PSUs cause they are build by either Seasonic or CWT. I dont like buying rebranded stuff tough, you never know if and when they silently switch suppliers (not that they do or did already). I`d rather buy a Seasonic PSU from Seasonic if you get my drift.

 

[Rys]

I've used Tagan since I did that big PSU test for Hexus, because the TopPower core tested so well, and the same basic high-end ATX recipe hasn't really changed since. My requirements are simple. 2 x 8-pin PCIe, very solid +12V and modular cabling. All good modern PSUs are quiet so that's a given.

Tempted by the very same PSU that I'm having problems with if I'm honest, but I can be drawn away by solid recommendations.