I have an unusual problem, which I hope I can get some help on?

First my computer specs

Case: Thermaltake Kandalf
PSU: Thermaltake Purepower 680W
Motherboard: ASUS A8N-SLI Premium
CPU: AMD Athlon 64 x2 4400
Memory: 2 x 1GB DDR 400 (Crucial)
Graphics: ASUS 7800GTX 256MB
Hard drives: 1 x WD 250 GB SATA II + 1 x WD 160GB IDE
Optical drives: 1 x Plextor DVD Writer + 1 x Plextor DVD combo
Sound: Creative Audigy ZS + Creative 7 speaker set up

History

I purchased and built this computer back in november 2005, and from building the computer I have had no problems, and use the computer almost every day to play games like doom 3, half- life 2, prey, NFS etc etc at high quality graphics settings, as well as doing the boring jobs of household accounts, letter writing, emails etc. The computer has been perfect and played all games very fast with no crashing issues etc.

Problem

I went away for a week (holiday) and on return, found that the computer will not turn on. When the power switch on the case is pressed nothing happens - Nothing meaning, no case fans, no case lights, no CPU fan, no graphics fan - nothing.

P.S. I noticed that the house had suffered from a power cut whilst away, due to having to go around a re-set all the clocks etc!!

I swapped the power lead from the back of the case (PSU) for the monitor one, but still the same!!

I then opened the case and checked the power switch leads from the case to the motherboard but everything OK, then checked the PSU connections to motherboard, but again all OK, and the green LED on the motherboard was ON, indicating power (some) was being recieved from the PSU.

Whilst checking out the PSU, I had disconnected the power cord and turned the PSU switch off, and then after reconnecting everything, I pressed the power button on the front case, and the computer turned ON and booted up with no problems at all!! Mystery.

I then shut down windows (XP Pro), and went to turn ON again and nothing!! Back to square one? I then disconnected and re-connected the power cord to the back of the case (PSU) and after a couple of attempts of doing this, the power switch on the case turned the computer on!

I have now worked out a routine, that if I remove the plug from the 4 way (surge protected) strip adapter and then reconnect, the power switch on the front case will turn the computer ON everytime - first go as normal(so far)!!

I suspect that the power cut may have caused damage to either the PSU or motherboard (even though I hoped the surge protected strip adapter) should have protected me from damage!!

I am requesting help from any member who may have experianced this problem before (with hopefully, an answer on fixing the fault), or a member who may have information on how to prove which component (PSU or motherboard) is at fault.

Like many people, I do not have a spare PSU or motherboard to swop to prove the problem?

I have already emailed both ThermalTake & ASUS supplying the above details, but at present (after 5 days) I still have not received any replies?

Can any one help?

Sorry for the long post, but I hope I have supplied all the information required, to obtain assitance.

Thank you in advance for any help.

Dave

Hi FriendlyDave1966,

Welcome to The PCHF,
Thanks for all the info on your problem, really good detail. I think that the problem more than likely is with your PSU. A way to test it is take the PSU out and put it into another pc, I doubt that it could damage anything else, but it would prove that it's either the PSU or the Motherboard. If it works ok in the other pc that would mean that the problem is with the Motherboard etc.
Keep us posted on your progress.

You might also check your surge protector. Surges/lightning can damage them too. If you have a meter, check to see that youre getting full voltage to the psu. If not, replace it with a known good one and see if that helps.