I have been trying to test a new (secondhand from eBay) PSU to-day for a secondary computer that I am preparing to build out of secondhand parts. The motherboard that I had originally had for the computer did not work (when tested with two different known good power supplies, would power the fans on instantly that the PSU hard switch was turned on, and refuse to POST or display anything on the screen; it was sold as "untested", so I imagined that it was broken). I was hoping to test the power supply soon, since I have yet to leave feedback for it on eBay, and wanted to test it before I did so.
I first of all tried it with an old Abit-BX6 motherboard that I took out of an old computer that I decommissioned last week-end, and that was working (albeit a little unreliably) at the time. I put in an old Pentium II Slot 1 processor (not the original from that computer; one that I had salvaged from another computer because it had its fan still connected and working), connected the fan, added some memory (not the original from that computer again, possibly something that had been in the computer before, but, in any event, clearly labelled "PC100", which is correct), and connected an old ATI AGP graphics card that came from the older PII system that I had taken apart for spares some time ago (again, working before disassembly). I rested the whole thing on top of an anti-static bag on top, in turn, of the new computer case (with the PSU in it, but as yet with no motherboard in it), and plugged in the PS/2 keyboard and the monitor.
With the new PSU plugged in, it started the fans, brought the monitor out of power saving mode, and briefly illuminated the NUMLOCK, CAPSLOCK and SCROLL LOCK lights on the keyboard, but would display nothing to the screen, nor would pressing NUMLOCK result in the light illuminating. I tried changing the graphics card, RAM, CPU (to the graphics card, RAM, and CPU that were originally united with that motherboard), all to no avail, and also tried it on the known good power supply that had happily been powering that very computer until last week-end. I also tried resting the motherboard on the anti-static foam, rather than the bag, in case of short circuit, but that made no difference. I tried two different spare PC speakers, including one that had been working last week having taken it out of that same system, and heard no beeps.
So, I tried another, slightly older motherboard, that had come out of the computer that the one that I am going to build is to replace, an old Socket 7 series computer, using an AMD K6-2 500Mhz processor, and about 512Mb of SDRAM. The original CPU and RAM were still in place on the motherboard. It had been working until sometime last year, when the PSU failed. It had previously been running from an AT PSU, it being one of those transitional motherboards that accepted both AT and ATX connectors, and I had never known it to run with an ATX connector before. I tried it first with the known good PSU, and shorting no given pair of pins for the front panel (i.e., the bank of pins including the power switch) seemed to do anything at all. I realise now that I had no fans connected (the old K6 CPU being safe to run with a heatsink but no fan for at least a short period), and the PSU fan had seized, but the PC speaker that I had connected made no noise, the monitor displayed nothing, and the keyboard lights did not illuminate, either independently or when pressed. Then, on reflection, perhaps somewhat unwisely, I shorted across two pins on the "Wake on LAN" header, and was promptly greeted with a large spark and a burnt PCB odour. I unplugged the keyboard and monitor, removed the graphics card, and wrote "probably dead" on the back of the motherboard in black marker. I do not care so much about the old CPU and RAM, but I rather hope that the graphics card is not fried, since it is a useful spare (Matrox G400).
Then I tried the motherboard from the old PII system that I had disassembled to extract the spares. I had to use the PII, rather than the PIII processor, as the thing had the older LX chipset, unlike my old motherboard's BX chipset. I connected the CPU, the "PC100" SDRAM that I had used on the BX6, and the ATI AGP card that had originally come from the system, and was greeted with fans and briefly illuminating keyboard lights on startup, but no beep, no toggleable NUMLOCK light, and no monitor signal with both the known good and the new PSU. Admittedly, that motherboard had been handled rather roughly since I had taken it out of its previous home, not anticipating that it would be used again, and had been handled without any static precautions for a while, although the same was not true of the RAM.
Having almost run out of old motherboards, I thought that I should quit whilst I was behind in case I was somehow cursed and fried anything else. (I should note at this point that I wore an anti-static wrist-strap connected to the earth pin of a power socket throughout).
Am I cursed, or very unlucky, or can anybody think of a more sensible explanation for all of my old hardware suddenly giving up the ghost?