View Full Version : PC Won't start: PSU/MOBO no power and/or no video

16-07-2005, 11:36 PM
I recently installed a new AsRock P4V88 motherboard w/ new ram, new 3ghz P4 prescott E and a new fan. I am having problems getting the computer to startup. If I plug in both the power cables from the power supply(the large standard one and the small ATX 12v one) I hear a short electronic buzz sound from the power supply when I press the power button, and nothing starts at all, except it seems that a current runs through the machine for a tiny amount of time as I can see the fan on the CPU move a tiny tiny bit.

If I remove the small ATX 12v cable from the motherboard, then all the components seem to get power and start running but then I have no video signal on the video card (I have tried different video cards-AGP+PCI).

Any Ideas?? I really need this PC running ASAP.

17-07-2005, 12:47 AM
what size PSU? i suuspect its to small.

17-07-2005, 12:56 AM
Hmm, I don't think that's the problem. I bought a new "Thermaltake Silent PurePower TT-420AD(DUAL FAN) 420W PSU" along with the new motherboard, CPU and ram. This is the exact power supply I have: http://www.newegg.com/Product/Produ...N82E16817153006

I have tried a different power supply, and the exact same thing occurs. No power with both plugs, and no video, but power with just the large standard plug.


17-07-2005, 01:16 AM
its not one of those boards where you have to hit the reset switch to get it to run for the first time ??

any jumbers, check everything is set to the slowest speed possible anddisable any power on features.

17-07-2005, 05:30 AM
If the CPU fan is running on the same 12 vdc that the drives depend upon for power, then I suggest that you disconnect a few of the 12 vdc dependent devices and try try again. It sounds like the PSU is thermalling out after a heavy current draw (read: short) and then cycles out to protect itself. I just bet it's in a 12 vdc device anyway. I know, I shorted out my PSU the same way a few weeks ago, and was going to go looking for a new one, but it thermaled back on after it cooled off. Phew!

Speedy Gonzales
17-07-2005, 10:10 AM
The videocards you've tried are 1.5v arent they??

As 3.3v will damage the system.

When u took the ATX 12v connection off, were there any beeps?

Funny that it would go without this. As normally, it wouldnt on most mobos.

As its needed to supply juice to the CPU.

The only other thing, it might be is the mobo maybe shorting on the case.

I would also make sure the CPU is the right way round. And in properly.