The light is on but the machine fails to boot

The light is on but the machine fails to boot

A friend's machine recently died. At first I thought it would be the power supply but now it appears the (green) light on the front of the machine is lit and the motherboard light is also on. When an attempt is made to power on the machine there is no feedback, such as a couple of beeps. I now believe it's more likely to be the motherboard than the power supply. Based on these symptoms, what's your diagnosis? I can temporarily replace the psu with one of my own if there is any ambiguity in the likely cause of the problem to ensure whether the psu is to blame.

Asked by: Guest | Views: 466

Total answers/comments: 3

Comments display order:

Guest [Entry]

"Change the PSU if you can - if you have spare one, perfect.

I had exactly the same problem and it turned out to be a bad PSU. PSU's don't always just completely die. Symptoms on my own computer began with random restarts. Then the computer would sometimes get stuck during boot and eventually it failed to switch on at all. The LED on the motherboard was still on so I was stumped on what it was. I swapped the PSU out (on a hunch) and everything has been fine since (6 months later).

If you're swapping the PSU, make sure it is powerful enough to cope with whatever components you have in the computer. You can get a pretty good idea of what you need with this tool here."

Guest [Entry]

"Actually the ""couple of beeps"" are important. Well, the count of them.

Some (most?) motherboards report low-level issues with beeps, as there is nothing else they can use to warn the user something is wrong (some have LEDs too). Too bad actually that the recent computer cases do not ship anymore with a speaker, or that the motherboard do not come with an on-board beeper.

Refer to the manual of the motherboard, they should indicate the possible cause of the issue for each number of beeps.

This type of diagnostic card is actually great to identify boot issues, as it reports with numbers the step the BIOS goes through when checking the hardware. And it has a speaker in case the case/MB doesn't have one. Helped me once to troubleshoot a computer not booting, it identified an issue with the USB controller."

Guest [Entry]

"You may want to try and resetting the CMOS settings (with the appropriate jumpers on the motherboard. The symptoms you describe sound similar to a problem with the Dell Dimension 5150

Alas, for the 5150, it only provides a temporary fix."