Tagan PSU woes :(

Messiah Khan · 13 Jan 2007 at 13:05

Im having some issues with my pc at the moment. The other day I was using my pc like usual, when all of a sudden it shut down. I tacked it down to being the fuse on the plug. I replaced the fuse and all was good for a while, until the pc shut itself down again. Turns out it wasn't the fuse, but the PSU. After a while, the PSU is switching itself off. It won't let you switch it back on again for a few minutes.

I thought it might be some sort of thermal trip in PSU going, so ive cleaned the computer, and vacuumed out any dust in the PSU and made sure that the PSU fan is still spinning(which it is). But ive now booted back up, loaded up speedfan to keep an eye on temps. the temp are fine, but caught my eye is the +12v line. Its sitting at just over 10v and sometimes dips down to 9.9v! This sutely isn't right. I would have noticed if it was doing that before, so it must only recently be doing it.

Why would a PSU all of a sudden start undervolting onthe +12v line? The PSU is a Tagan TG480-U01 480W, and has been running happily for over a year now. I havent got a hugely demanding system, and I havent added anything recently. Anybody got any ideas or suggestions?

subzero · 13 Jan 2007 at 13:14

Sorry to hear this,the exact same thing happened to my previous psu.The 12 volt line kept undervolting and was never stable afterwards... shutdowns,bluescreens and system lockups.

I had to rma it in the end,since getting my new one i have had no problems at all...although what would cause the 12 volt line to fail in the first place i have no idea,maybe it was always a weak spot in my psu and grew worse over time.

Theguy · 13 Jan 2007 at 13:14

Touch wood, my 380 targon has been lovely. that is rather strange about the 12v line though, maybe you had a power spike type thing which did the fuse in, and at the same type dodgyed up your psu?

or it could just be broke, in either way, u cant live with a 12v line of 10v, you might have to send it back.. at lest they have like 2/3 year warranties on them, so shouldn't cost you much?

another thing though you might want to consider, speed fan might not be reading the v correctly?

sorry cant give you a proper answer :/

Messiah Khan · 13 Jan 2007 at 13:27

Pretty much what I thought tbh

Are there any other tools to diagnose the PSU? Ie to read the +12v and +3V line and thermal probes etc?

Theguy · 13 Jan 2007 at 13:34

messiah khan said:
Pretty much what I thought tbh Are there any other tools to diagnose the PSU? Ie to read the +12v and +3V line and thermal probes etc?

i guess the only way you could do it and know exactly, would be some kinda volt meter type thing, but god knows how much those cost. i haven't used 1 of them since gcse times...

sorry m8y!

Messiah Khan · 13 Jan 2007 at 13:52

Theguy said:
i guess the only way you could do it and know exactly, would be some kinda volt meter type thing, but god knows how much those cost. i haven't used 1 of them since gcse times...

sorry m8y!

*Gets dressed and heads off towards B&Q*

Messiah Khan · 13 Jan 2007 at 14:14

Well it seems to be getting worse. The PC is freezing half way through the POST now. But on the bright side, ive found the receipt from December 2004, and Tagan have a 3 year warranty. Does anyone know how fast and how good the Tagan RMA service is?

killer_uk · 13 Jan 2007 at 14:16

messiah khan said:
Well it seems to be getting worse. The PC is freezing half way through the POST now. But on the bright side, ive found the receipt from December 2004, and Tagan have a 3 year warranty. Does anyone know how fast and how good the Tagan RMA service is?

Took me about a week to replace mine, excellent service. Would it be alright if I just send you a quick email to your msn address?

Messiah Khan · 13 Jan 2007 at 14:18

killer_uk said:
Took me about a week to replace mine, excellent service. Would it be alright if I just send you a quick email to your msn address?

Cheers. Did you have to post the old one off, or did they send a courier? Yeah go for it mate.

killer_uk · 13 Jan 2007 at 14:23

Your MSN one bounced back, so I've sent it to your main email address (the one in your trust profile).

messiah khan said:
Cheers. Did you have to post the old one off, or did they send a courier? Yeah go for it mate.

I had to post the old one. Can't remember how much it cost. I think it was around £7. You could always ask them if they can send out a courier.

subzero · 13 Jan 2007 at 14:27

Dont know if the procedure is still the same,but when i swapped mine it was a door to door courier service and took a week,very good service...just exchanged psu,s with the guy that brought the new one.

Messiah Khan · 13 Jan 2007 at 14:28

killer_uk said:
Your MSN one bounced back, so I've sent it to your main email address (the one in your trust profile).

I had to post the old one. Can't remember how much it cost. I think it was around £7. You could always ask them if they can send out a courier.

Weird. But that second email worked, cheers. Im off to get a multimeter in a bit to make sure its the PSU dying, but im fairly sure it is now. I wonder if an unbranded 300W PSU will be enough to keep my pc running for the moment. I know it would be a risk, but going 5-6 days without my pc!

Im using my parents at the moment and its horrible.

subzero said:
Dont know if the procedure is still the same,but when i swapped mine it was a door to door courier service and took a week,very good service...just exchanged psu,s with the guy that brought the new one.

Thanks. At least the RMA service sounds better than when I had to deal with Xerox.

Messiah Khan · 13 Jan 2007 at 16:23

Well ive just bought a multimeter and checked the voltage, and its all fine. The +12v line is well within spec. :confused:

So it was just Speedfan lying. But the computer still keeps turnimng itself off. Whenever it turns itself off, I can't restart it. to restart it I have to switch the main power switch on the back of the PSU off, leave it a while, then switch it all on again. so its like something needs resetting. anyone got any ideas?

Edit; Oh and one thing I noticed is that the small blue LED on my motherboard (MSI K8N Diamond) keep flickering. Should it do this?

Reality|Bites · 13 Jan 2007 at 19:15

MSI is your problem

Try a different motherboard if you can.

Theguy · 13 Jan 2007 at 19:31

Reality|Bites said:
MSI is your problem

Try a different motherboard if you can.

lol why would having a msi board be the problem.. hes just started getting the problem hes had the board for ages.. anyway moving on.

rather dodgy m8y. the fact that your volts are all good, and just shows how crap speedfan is for showing volts. i say you should get a replacement psu and just hope its that and not something else? probably all stems back from that blown fluse.

w3bbo · 13 Jan 2007 at 19:43

Are you testing the PSU under load? If you are testing the PSU with nothing else connected it might well be fine but if you add everything else in that will be taking load from the 12v rail then it might just be too much for the PSU to handle hence the undervolt protection your experiencing.

Messiah Khan · 13 Jan 2007 at 20:13

I was taking the reading off a spare molex plug when my full rig was connected, so it was under load. Ive now tested the PSU on its own as well(Removed it and hotwired it) and it ran flawlessly for ages. So im now thinking its the motherboard. Reality|Bites, why did you think it was the motherboard? Ive had quite a few MSI motherboards, and they've all preformed very well. Im going to keep testing to see if I can narrow the problem down. Although if I can't get it sorted I might end up getting a second hand DFI mobo. Although im half tempted to get a cheap conroe setup. Really could do with saving the money though.

mcc49 · 13 Jan 2007 at 21:42

I contacted Tagan recently as it started to develope loud ticking sounds, they responded within 24 hours but they insisted on me sending them the PSU at my expense for testing before they will send me a replacement. I need my PC daily for work so that was out of the questions as I dont have a backup PSU, so at the end of the day I was left with a ticking PSU and a quite poor experience with Tagan.

Messiah Khan · 13 Jan 2007 at 21:49

Thanks mcc49. But im fairly sure its the motherboard now rather than the PSU. Ive stripped the whole pc down, and ive just got the rig out on my desk. Ive tried most combinations of hardware etc, and nothing has seemed to fix it. I really could do without having to buy a new Motherboard now as well.

Messiah Khan · 16 Jan 2007 at 09:36

Well after taking everything to pieces and putting it all back together again, it seem to be bahaving itself... sort of. It no longer is randomly shutting down. Infact it is doing quite the opposite. I can use my computer fine, but when i turn it off to go to bed, after a minute or so it will automatically switch itself back on.

Im having to resort to switching the main power off at the back of the PSU to make sure it stays off. Any idea qhat would cause this? I really want to get this sorted as im getting Phase and watercooling soon, and I don't want it to start playing up again after ive got everything bolted together.