Antec HCG- 850M PSU wont work

[BOKY77]

Hello. I have Antec HCG- 850M PSU and it running amd 7990 powecolor GPU.
CPU is q9650 and MBO is gigabyte GA-EP45-UD3R, 8 gb ddr2
I have some odd problem because PC runs fine for about a week and after that it start to shutdown by itself and it wont boot. When I press power up button lights on MBO and GPU goes on, fans are spinning but monitor has blinking power button and no BIOS.
If I leave PC for one or two days and I do not power it up it usually starts and everything is back to normal for one or two more days. After that its same thing as iv described.
Iv tried everything, removed MBO, CPU, thermal paste, RAM, PSU and GPU, SSD... Only if I put other PSU and GPU it works like charm. Iv tried 7990 at my friends PC and it works perfectly and iv send PSU to official repair servis and they told me everything is fine.
So this is real mistery for me because every single component is working with no problems.
What can happen for PSU not to work after one week of moderate use and to work again like nothing has happened if I remove it from case and put it to rest for couple of days?
Thank you.

 

[brispuss]

It seems possible that the Antec PSU might have an intermittent fault, which is hard to diagnose as it can take some time to locate the fault.

With all original components installed including the 7990 video card, except another PSU was installed instead of the Antec PSU and the system worked OK? If this was not done then please try it. Only change the PSU leave the other components installed.

If the system works OK with the test PSU installed then there is a problem with the Antec PSU. If the system still doesn't work then the problem is elsewhere.

If the Antec PSU is suspect then maybe try it in another computer to confirm that it is faulty. If it seems that the Antec PSU is definitely faulty, then insist the repair service people do a proper (long term test). I suspect previously the service people just switched the Antec PSU on and just took basic voltage measurements without actually loading the PSU and without monitoring it over a long time period.

 

[BOKY77]

Hello, thaks for replay. Ppl from servis told me that they have put PSU under 24h test and under serious stres test so they say its working ok. Could it be some static that cant interfere with PSU, iv tried everything , pulling out battery ,power cord and pushing power button for 1 min...

 

[brispuss]

Try again.

Was the Antec PSU only uninstalled temporarily and another PSU installed in its place as a test of the computer?

If yes, did the computer behave with no further issues? If yes, then the Antec PSU is probably faulty. If no, then the fault may be with the motherboard or other component(s).

Was the Antec PSU only tried in another working computer (temporarily replacing the other PSU in this other computer)?

If yes, did that other computer have issues? If yes, then the Antec PSU is probably faulty. If no, then the original computer has a motherboard and/or other component fault.

 

[BOKY77]

Another PSU was installed on my PC ( as a replacement of Antec PSU) and it runs with no problems. But Antec PSU was installed in another PC ( servis PC) and they were doing 24h stress test with no problems so they concluded that Antec is not faulty.
When I install Antec on my PC it runs with no problems for about 7 days and then starts to malfunction( resets PC ) and after one or two days when I hit power button nothing happens except that fans spins, lights on MBO are fine and power LED on monitor is blinking.
I just cant figure what is wrong with it...

 

[brispuss]

OK. Thanks for the clarification.

It seems there is an intermittent/slow/early fault with the Antec HCG-850M PSU. To check this requires running the PSU and/or switching it on/off for extended testing periods for a week or more. Testing over 24 hours may not pick up all faults.

I had a similar situation in that a PSU that was just beginning fail but would work OK for awhile and then sometimes have trouble starting the computer. The service people I sent the PSU to claimed the PSU was working OK, but I insisted that there was a definite problem with it as a replacement PSU ran my computer fine.

Eventually my PSU was sent away for extended testing and was found to be faulty after all! I got a replacement PSU under warranty.

It is suggested here that the Antec HCG-850M be subjected to extended/more thorough testing to confirm that it is faulty. Insist on this extended testing being done! And mention to the service people that a replacement PSU runs the computer OK, therefore the Antec HCG-850M HAS to be faulty!

 

[BOKY77]

Thank you for your kind answer