I am beginning to suspect that the single clip stand-off at the center of my case's mobo tray is causing occasional shorts on my motherboard. This is my case: SilverStone TJ04. It's old, but has served me well mostly.
Last night, after dealing with all kinds of issues, I attempted to boot my machine with some additional RAM. This resulted in the LEDs on the mobo flashing in time to the power and DVD-ROM LEDs, accompanied by this horrible "clacking" sound that repeated with each flash. I shut down the machine, removed the RAM, leaving just the original 2GB stick, but the same flashing occurred. Even when I removed the RAM, it still happened. So I turned off the PSU, unplugged it all and went to bed.
This morning, I unscrewed the motherboard from the tray, lifted it all out and set the mobo on a piece of raw cardboard. Situated just so, I was able to boot up the machine without incident.
That done, I carefully placed the motherboard back on the mounts in the tray, screwed them in and plugged in everything but the floppy and the IDE to the DVD-ROMs. Booted again without incident.
Finally, I plugged in the IDE cable (located on the bottom of the mobo) and the floppy cable (located at the center right, facing the side of the case). The flashing started, albeit intermittently, without even touching the power button. I unplugged the IDE and floppy, turned off the PSU and unplugged from the mains, but it still gave me a few flashes after that.
Could I get away with not using that center stand-off? I'd be concerned that video card installation would be dangerous without the support. Are there non-conductive plastic alternatives to the metal clips? Like maybe these guys? Or do I just punt and get a different case?
I have a few of the plastic standoffs in my junk box. Over the years, I have used a couple to support motherboards when needed. Both times I simply cut off the small button on the base, then used them for support. With the small button removed, you cannot anchor them to the mb tray, but that's no problem. The rest of the standoffs and screws hold the motherboard in place.
If you really like your case, that's a better alternative than replacing your case - and cheaper too.
I'm probably going to look into getting a few of the plastic standoffs, but now I'm wondering if perhaps the little cardboard washers are to blame. From what I can gather, some of the motherboard's mounting holes are metalized and some are not. If a washer is used on a metalized hole, it doesn't ground properly to the case.
So maybe I need to remove some washers?
Only question now is, do those same holes need washers on the underside, between the mobo and the standoff? Do all the mounting holes need them?