Posted 22 November 2009 - 01:57 AM
Several baddies can cause the power up issue you describe. A failed, shorted, video card, a bad power supply fan, system device failure(shorts of all kinds). Any thing that consumes power from the power supply on start up can cause such failures. In your last post you mentioned jumpers. I 'm not sure if your referring to th e jumper test for starting a power supply( PSU= power,supply,unit ), but this test can be used to power up the PSU for a cool start, so to speak. Without the complete system start up draw. Even doing the testing would require some lead work on your behalf though.
In order to replace your power supply you have to become familiar with all the connections inside the PC first. This is important for testing your unit as well. You can test for shorted components by disconnecting there power connections. label any thing you disconnect and and only do so to drives not used for booting up. You need to have the hard drive available for boot but it could be a source of trouble as well, so maybe check it last. A video card(powered or not), floppy drive , second hard drive , cd drive , and system fans can cause a power supply to fail safe out ( turn off).
Did you experience any other abnormal behavior before this failure.
A PSU is not a real hard to replace item, But to get all items in the system unplugged and then re plugged in is a task. Be meticulous in your notes as to all connections removed, then reverse your list as you reinstall. In most cases the MOBO power connections the toughest to get at, but its doable for most. Just apply gentle force when reattaching power connections , and always be sure that connectors are in proper correlation to sockets and pins. When removing connections be sure your not fighting against socket locks. Some sockets have retainment keeps that help secure the plugs, so look at the connections well before to much force is applied for removal or reconnection.
I have had a video card that caused the same symptom. In that case, I had no warning. The system would not start. Fans ran for a moment then all would shut down. The vid card had a cooling fan stop and over heated several capacitors in turn drawing to much power(shorted) from PSU upon start up and caused it to fail safe off.
For any of us to offer a good referral for a possible replacement PSU we need to have a description of you pc and a list of any mods that you have made to it. I see you mention HP media center. Some one here will know more about its specs, than myself. By looking at the label on your current PSU you can tell what wattage not to dip below in stock configuration.
(new,12/23/09) ASUS Crosshair III, Phenom IIx4 955 Blk Ed, Zalman 9500 HS, Saphire 5770 vga, W-7/64bit, 8g/Corsair/1600 RAM, 850w HX Corsair PSU, WD CB/500gb HD, Pioneer CD/DVD, Smilodon/Dirk-Tooth(modded), All custom&controlled fans. Shhhh lol