Hello everyone. My friend has a Pavilion a000 desktop that won't power on, so I'm trying to troubleshoot it. The first thing I notice is that the LED on the back (next to the AC inlet) is blinking. So I take the covers off and start taking power connectors off, and I discover that when I disconnect the 20-pin ATX connector on the MB, the LED stops blinking and turns on full. If I plug the ATX connector back onto the MB, the LED stays on full, and the unit will boot normally. When you power off the machine (and disconnect the power cord) the same problem happens all over again. My thoughts are that the MB is bad, but maybe it's the power supply. I wanted to swap another power supply in and try it, but I don't have one. Any thoughts? Thanks in advance.
Thanks o1die. I agree that this thing has a low-end PS in it, but why does everything work after I unplug and replug the MB connector? Does it have something to do with the PS_ON or the PWR_OK signals?
Another cheap fix is to replace the motherboard battery, and try reconnecting all the power supply connectors. If you decide to sell the board, I might be interested, as I still have an hp vista license.
Update - I followed the troubleshooting guide found on HP's web site, and it points to replacing the motherboard. I reviewed my findings with my friend, and they elected to work around the problem by disconnecting and reconnecting the ATX connector whenever the unit wont boot due to a power failure or disconnection of the AC plug. So I still don't know if the problem is really with the motherboard or the power supply, but my friend doesn't really want to spend any money on it, so he'll limp along with it until the next major issue. Thanks to o1die for his interest.