A client had an HP P2-1394 model H3Z88AA desktop system that would turn on briefly, the drives would power up, the fans would spin, and then the system would shut down. After about 5 seconds the process would repeat. This would continue until either the power was removed or the power button was pressed for several seconds forcing the system to the off mode.
Some technical notes found on similar issues suggested the following:
We checked out the power supply found nothing wrong. But for testing purposes we tried a new power supply. Still the same issue. The system repeated the start up and shutdown process.
Next we removed the original RAM and install new RAM of the same type. No change, the system just powered up and then shutdown never providing any errors or video.
We then removed all of the peripheral device connections from the motherboard to see if the motherboard was having power issues caused by the devices. The same issue persisted. However the only change we were able to force was when all of the RAM was removed. At that point we were able to get the motherboard to provide a beep code indicating that there was a RAM configuration issue.
Our final conclusion with out having any additional diagnostic tools specifically for this motherboard was that the motherboard itself was defective. Unfortunately this computer only had a one year warranty and so it was up to the client to decide if they wanted to purchase a new motherboard or just get a new computer.
We hope that this information is helpful. Please let us know how this has helped you or if you have additional questions. As always Firestone Technical Resources, Inc. is here to help with your computer support issues - "Providing personal service for your impersonal technology."