Power Supply?! Please help diagnose issue

blaze3000

Honorable
May 20, 2016
9
0
10,510
Hi,
Please help me diagnose the issue here. My PC won't power up today, was running fine yesterday. When I push the on button, it lights up and flashes momentarily, but the fans don't start and nothing powers up (no noise whatsoever), so I presume something's been triggered so that it can't startup unsafely. Here are the details I can get (sorry, rest were on the PC!)

PC model: Advent PQD6002
MB: Foxconn A6VMX
CPU: AMD Phenom x4 64bit (don't know the precise model)
12v dc brushless CPU fan
12v dc brushless fan on back of case
Power supply: ISO-400PP

I am handy enough to change one of the above, but I have no idea of diagnosing which is at fault. I have cleaned all the dust from the fans and heat sink, but still no change. I have read about replacing the button cell battery, but won't that reset the BIOS - and is that even related?
Update: Just prior to ihog's comment i changed the cmos battery- obviously no change.

Would be really grateful for any help.
 

ihog

Distinguished
Replacing the battery resets the CMOS, as in the settings of the BIOS. Just sets everything to default settings.

Sorry, but this is one of those issues that is difficult to troubleshoot over a forum, so I'm just going to give you this bump. Good luck.
 

blaze3000

Honorable
May 20, 2016
9
0
10,510



Thanks for the bump. It's a fairly old machine (c. 8 years with no issues), my guess is it's either one of the fans or something to do with the psu. The fact that the light around the power button comes on makes me think it can't be the PSU - otherwise no power would be getting through?

On an older machine many years ago when the fan didn't work, it would still boot up, then crash with a temperature warning sign on the screen. With this machine that isn't the case. Do you think this is a mechanism for protecting the PC? I can't find a manual or documentation online.