I've got an IBM x346 that was (supposedly) working fine in the past which will no longer post now that I've taken it back out of storage.
When I power it up, it seems to be permanently stuck in an endless cycle of almost posting and then reseting. It doesn't get to the beep codes, but does periodically flash the boot logo momentarily on the attached monitor, and the 2x8 segment post display is in constant flux. If I remove the memory, it properly lights up the missing module indicators (by the dimm and on the lightpath), and emits the out of memory beep code. It does the same thing if I install dual-rank dimms (obviously, this machine shouldn't support that).
I've pulled all the acccessory cards and risers that can reasonably be removed, taken out the drives, and still this endless post cycle. I've tried both power supply modules. I don't have another similar machine handy, or I'd start swapping in the more important bits.
Any advice on where to look next? Anyone else seen this behavior?