Hi,

I really need help now, as I am throwing money at a problem to no avail.

When I got back from holiday, my desktop PC was strangely dead. Its quite old, ASROCK KVM72 mobo, AthlonXP 2400, 1GB RAM, GeForce 6200 AGP.

I suspected the PSU had given up the ghost, so bought a new one. No difference.

Next I thought the mobo must have been fried, so i got a new one from ebay, Gigabyte GA7VA r2.2, which I know for a fact is compatible with my other hardware.

First time I turned it one with the new mobo and it booted the bios, recognised the CPU and RAM OK. Then said NON SYSTEM DISK, which was no surprise since I'd forgotten to connect the HD power!

I turned it off, connected the HD power, and tried to start it again... Nothing. All that happens is the tiny RAM_LED on the mobo lights. Reset button has no effect, holding down power for 3 seconds causes the RAM_LED to go out. When it goes on I can hear a tiny click from the PSU, like it is turning on. No CPU fan, or screen activity.

I've been through various tests, running with various hardware removed but no change.

Is my CPU fried too??????

Thanks for any advice

Simon

What about the fan in the power supply? Do you possibly have a voltmeter to do some checks?
Mark

Hrm it worked with the HDD unplugged try without the HDD again and see if the computer will post. If it does be sure that the HDD cable is plugged in properly I know old ones can get plugged in upside down if there not keyed. If it still doesnt work with the drive plugged in I'd be looking for a new one.

No, no PSU activity, and it doesn't work without the HDs plugged in either. It just worked once.

I know that a MOBO can start without memory, and will beep a certain no of times to reveal the memory problem, but will it turn on without a CPU?

I am wondering if I had PSU failure which nuked MOBO, CPU and probably RAM too?

Maybe I'm misunderstanding you, but if there's no power supply activity - it's the power supply. If it's an ATX P.S. the momentary button might not be connected properly, It doesn't need to be in the case connected to everything to work. You can run it out of the case on the bench. Maybe you've bought a bad one or it's underpowered Power supplies can be quirky. It doesn't save any money to buy a cheap off=brand one. Are you sure all of the connections to the mobo are correct?
Mark

I guess thats possible....

its 400W, and it seems strange that two PSU aren't working... I'll test again later

You can determine if the PSU is the problem with a voltmeter. Turn off the PSU by the switch on its rear or unplug it from the wall. remove the 20 pin connector from the motherboard and place a wire jumper between the green wire socket and any black wire socket, this bypasses the motherboard to turn on the PSU. Turn the PSU back on and use the DC scale of the voltmeter to read the different rail voltages.

This site will provide you with the color code and the associated rail voltages.

You might want to make sure that you motherboard isn't shorting to the case where it is mounted.

It could be a short. Have you tired starting the machine outside the case? With just the CPU and memory plugged in and the motherboard on some non-conductive surface?

My apologies where I missed that the power supply wasn't working, Follow the advice given and we can go from there.

Make sure your wall socket is good (plug a lamp there). I don't know if this is still the case but Power supplys used to have 2 settings, a 220 or 110 setting. Make sure that it is set correctly for your power outlet.

Ok, heres an update:

I've got new PSU, mobo and CPU now.

When I powerup the system on the bench, it turns on for 5 seconds and turns off (PSU fan comes on and mobo light lights, 12v on yellow wire, 5v on red thank god!).

Now the only pieces still of the original system are the RAM and the mobo battery... could it be the mobo battery?

Thanks

Si

I have seen stranger things happen check it with the voltmeter, have you tried the ram in a different computer it could be faulty too. Has the computer made it to the post screen? Have you made sure you have connected ALL of the power connections to the computer. In newer systems along with the 20/24 pin ATX connector on the motherboard there is an aditional 4 pin CPU connector that needs to be plugged in as well.

Is there thermal paste between the new CPU and the CPU cooler?

It's probably not the mobo battery (they generally don't cause these symptoms) - but they're a heck of a lot cheaper than new RAM!

I'd opt for testing the memory in another system - that'll tell you if it's the memory or not.

Well, I think I can discount the ram. That mobo will produce the beeps signifying missing or faulty ram if that is the case.

Its a direct replacement for the mobo I had before, so it doesn't use the extra 4 power connectors.

It doesn't make it to POST screen

I'll get a battery on the way home from work

Usasma asked a very important question about using thermal compound or a thermal pad, with out this the CPU can over heat very quickly and will shut down the system.

It looks like you're doing a minimal build on the bench, but be sure that you have no motherboard shorts to any other objects.

Have you cleared the CMOS?

Ok, problem is SOLVED but at a heavy cost.

Destroyed in PC meltdown:

PSU (the culprit!)
Motherboard
CMOS battery (eh?!)
80GB maxtor HD
20GB maxtor HD

Ouch!

Thanks for all the advise... oh and BACK UP ALL YOUR S*** NOW!

wow how did you find out what was cooked? glad you got it running again