Slightly annoying.

Alright ladies and gents, and other sentient beings on the MG forums, I've had this problem for a little while now, basically right from when I first built this machine, after I turn it off, and turn it on again, It'll power up, lights'll come on, then 3 seconds later it powers off. Now initially it wasn't so bad, it progressively got worse, to the point it wouldn't stop doing it. I did some troubleshooting and came to the deduction it was the PSU (it was a Thermaltake 720W) I've heard Thermaltakes have some compatability issues and with a different power supply it didn't do it. So i purchased myself an Antec 850W Signature Series PSU. Wella, works perfectly again. But a few months later, it starts again. Now the wierd thing is, depending on how I turn it off, makes a difference to how many times the cycle repeats. If I turn it off via the start bar shutdown command, it can be 15 minutes before my PC will start up. If I turn it off at the power, it's only 5 minutes. Thing is, since I've had the problem, the Graphics card has been replaced, as has the HDD, as has the PSU, and I've reformatted once and changed OS too ... leaving the RAM, case, ODD, CPU and mobo. Thing is the ODD is unplugged atm and the symptoms remain. I know its most likely the mobo, but atm I don't have the funds to replace anything. Any other ideas or things to try? Oh also I've tried a new CMOS battery etc.

 

Maybe a defect in the motherboard is causing the PSU to fail. Does the following help.

Unplug the power supply cord.
If the PSU has an on/off switch, turn it to off.
Hold down the power on button of the computer for 30 seconds.
Attach the power cord.
Turn on the PSU switch if present.
Press the power button of the computer.

This drains the capacitor of the PSU. Some people have had luck doing this when there computer will not boot up. If it does work, then the PSU probably has a problem that was caused by a hardware glitch in the motherboard.

 

And, if you do decide it's the mobo, check out the OEM's support forums for similar issues - there may be updates available for your model that address your problems.

There is another thread here (naturally, I can't find it at the moment) that mentions false temp readings in BIOS causing random shutdowns, and there was a BIOS flash that solved the problem.

 

I actually found that it used to tgell, eventually it stopped helping. As I said since then I've changeed PSUs and it stopped for a while then came back again.

And yeah Caliban I've already flashed to the latest BIOS.

 

Well, like you said: you're left with only a few possibilities. Try the RAM dance: reseating modules, swapping, trying one stick at a time, etc.
You might consider pulling the CPU, cleaning and reapplying thermal paste, etc.
For that matter, since the symptoms started from day #1, try checking the motherboard standoffs, make sure nothing's shorting.

 

lol the RAM dance never heard of it put that way before.

Come to think of it, last time it wouldn't start up, I removed and cleaned the RAM and swapped slots and she fired back up again ... I guess it is a possibility ... thing is i don't wanna waste money on new RAM stick if it is cuz I'll probably rebuild within the next ... say ... year or so ... and I'll upgrade to DDR3 ... shouldn't it come up with a memtest check if it was a RAM problem anyway?

 

Memtest, while a good tool, isn't perfect. Swapping modules not only tests the sticks, but also checks out the mobo's memory slots. The main thing you're looking for is a change in symptoms.

I copy the not wasting money, though - if you're gonna upgrade anyway, and you can live with the powerup weirdness, why bother?

 

Yea that's what I'm thinkin. I just decided to post to see if its something little or a little trick someones come across. If not, ah well, I guess I'll just put up with it till I upgrade.

 

If you live in a high humidity area, moisture might be the problem. Copper contacts have a problem with corrosion. If it worked after you replaced the power supply and then started to have the problem again, it may be contacts are the problem. Try unplugging the the contacts once or twice on all contacts and maybe they will be clean enough to work again.
Look for anything green and clean with alcohol and a Q-tip.
Jerry

 

Yeah, it actually is a big problem around here. One problem, I already did what you suggested ... I use a rubber to clean the crap of them then a normal piece of paper for light abrasion, cleaning off after with an anti static brush.