Crashing during factory reset

OK, I've started another memory test, just to make sure.

Once it's done, I'll try it off the UPS. BTW, when I was setting up the memory test, I noticed that the LED front panel only seemed to acknowledge the presence of the disk in slot #1 (disk #6), even though disk #5 was also there in slot #2. Not sure I want to read too much into that, as of course it couldn't boot with only one disk either, but maybe a bit more disk scrambling is in order.

Is there an straightforward way to test the PSU? Basic power is getting where it has to go, obviously, but there might be spikes or other misbehavior. I can figure out how to replace that if there's any way I can reasonably attribute these problems to power (as opposed to permanent damage elsewhere that might have occurred because of power issues).

If it isn't the RAM or PSU, though, dare I assume that nothing else is really user-serviceable?

thanks
Thom