How to diagnose PSU failure


Jul 13, 2007
Dimension 4700, Pentium 670, 4gb, original PSU, MB.

Experiencing a primary SATA drive not found error on boot.error is frequent (95% of boot efforts) but not 100%. Initially suspected the OS drive as it is very old so invested in a new SSD and installed it. Installed Win 7 Home Premium on it and all seemed well. A couple of days later, same issue, Primary drive not found.

Tried swapping SATA connectors and cables to see if it was a bad cable or connector, same issue on all ports will all cables. Turned it all off and left it as I did not have time to deal with it.

Yesterday, tried reconnecting OS drive only and booted. Lo and behold, it boots up. Added second drive back into the mix, error reappears. I am now wondering if the PSU is going away and is not providing enough juice to the drives. One drive is an old seagate Sata I 250 Gig, the newer is a Kingston SSD Sata III 60gb for the OS. Both drives seem to work fine when connected to other machines.

Would appreciate any thoughts on confirming the problem and a path to resolution (other than replacing computer)

Thanks for any comments.


well... sounds more like a motherboard issue then a psu issue...

you can see if cleaning up the system will help. get yourself a few cans of compressed air. clean out the system from top to bottom. make sure to get behind the motherboard tray.

You can also test out if it's the psu by borrowing someone's psu that WORKS. plug it in and see if the system will boot normally.