New CPU arrives...

and STILL no difference in behaviour. This (much less dusty) B2040 (EV5/300) CPU causes the system to behave like the non-SYSTEM RESET CPU i.e.: no OCP wakeup, no report of NO MEM INSTALLED when the memory is removed, etc. So: now two CPUs behave like this, the other shows SYSTEM RESET. Sigh.

I noticed that the replacement IO board was pretty beaten up, and finally noticed that it was actually missing a capacitor on the rear. This isn't affecting anything so far, but is now unlikely to be kept except for parts if a working system is ever forthcoming.

Wondering whether the original IO board's DALLAS DS1287 RTC clock chip had run out of juice, I scratched off enough of the epoxy covering to expose the pins and measured it: 2.80V

So, that's likely enough juice to get the system working. So WHERE is it failing?

Because the replacement IO board (B2110-AA) is so beaten up, I decided to order another IO board from Ebay. I am singlehandedly keeping the courier market alive...

If that one doesn't help things, time to look to the three remaining boards: the 54-23151-01 remote ports board, the 54-23180-03 OCP board and the 54-23260-01 fan control module.

Then there are the cables... To get the SYSTEM RESET / NO MEM INSTALLED OCP display, all that is needed is the OCP cable from the IO board to the OCP module. So that seems OK.

The disk cables can't be required to work to get the SRM running. The remote ports cable links the IO board to the serial ports, keyboard ports etc. block. This would obviously be required to view the console output (assuming it isn't being channelled to VGA, but that will come later), but I can't see it being required to be connected for SRM initialisation. Either way, I've tried it connected and disconnected, and no change.

Roll on the next IO board...