Diagnosis Help!

My machine's broke! The short of it is that my homebrew system stopped working after two years of operation. Now, the power supply will not turn on (fans start, but then stop immediately). I replaced the power supply with a new one, but the same thing happened. I called Tyan and got an RMA for the board (Tiger 133). This weekend, I went to the computer show and bought another Slot 1 board to use one of my cpu's (PIII 733mhz). I removed the old board and put in the new one (Asus P3V4X). I put one of the cpu's, and AGAIN the power supply would not turn on (brief turn of the CPU fan, then nothing). I tried the other cpu with the same results. Could it be both CPU's? Could it be the (admittedly) cheap cabinet? Is there some way to rationally test this thing without replacing everything piecemeal? Just before the computer failed for good, I was able to get into the bios. It was unable to see either hard drive. The two CPU's were at about 80 degrees F (where they are usually), and the voltages seemed normal. After shutting down this time, the computer would not come back up. I have removed all boards except the PCI video, but nothing seems able to bring it back to life.
Any help would be greatly appreciated!
6 answers Last reply
More about diagnosis help
  1. MEMORY..................

    You can also disconnect the hard drive and CDROM then try to boot to A:\ with a Win98 boot disk. The only things you have to have to boot are CPU, RAM, video and floppy. If it will boot to A:\ like this, then add each component until the bad part shows up. I still think it's the memory though.


    "You can run, but your punk ass will only die tired!"
  2. Considering that the CPU is the only thing you haven't tried exchanging, its very likely they are toast. Try removing the CPU(s) and then press the power-on button (keep the HDs connected just to provide a minimum load for the PSU). If your PSU starts up, your CPU is fried and is shorting the power supply.

    <i><b>Engineering is the fine art of making what you want from things you can get</b></i>
    <A HREF="http://www.btvillarin.com/phpBB/viewtopic.php?t=655" target="_new">My systems</A>
  3. Thanks for suggesting removing the CPU. I connected the drives (just the power, not the data cables), removed the cpu and the memory (and the video card). Still nothing (PSU fan starts to turn, then stops). I tested the switch with an ohm meter; it does short when you press it (I imagine that's how it is supposed to work). Could the new MB be installed incorrectly? I've assumed that if there is metal on the mounting hole, it's intended to be a ground point and should be connected to the chassis. Bad assumption? Should I be using fiber washers? Of course, this doesn't answer why the first one failed after two years.
  4. I think it's fixed! I tried running the MB out of the chassis. It ran with the old PSU. When I disconnected all peripherals (like fans, drives, and such), it ran with the PSU in the case. I got the Tiger 133 connected, with both CPUs, but out of the chassis, and it started working, too. I installed the board back in the chassis, and it worked. I reconnected each of the peripherals, but now things work with everything connected. I love intermittant problems:-)!
  5. Great. So what was wrong? Did you ever find out?

    <i><b>Engineering is the fine art of making what you want from things you can get</b></i>
    <A HREF="http://www.btvillarin.com/phpBB/viewtopic.php?t=655" target="_new">My systems</A>
  6. I assume that something in the cabinet (a fan, or one of the connectors to a drive) developed a short that kept the PSU from coming on. I didn't find the culprit, though! Not very comforting, is it?

    <P ID="edit"><FONT SIZE=-1><EM>Edited by natrella on 11/13/02 09:40 AM.</EM></FONT></P>
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