More email exchanges with Greg Bek and Michael Druke, both ex-Rational people.
Our IOC board does actually have 72 64K*1 DRAM chips, four banks of 18 chips.
Read the EEPROM from the IOC board, and have started disassembling the self-test code, to find out what it actually does.
Powered up with only IOC and RESHA boards seated, same result, which at least means that we can test in that config.
Also tried powering the IOC board up out of the cage, but our +5V supply can only deliver 7 Ampere, and that's not enough.
Greg Bek replied to email and told me I was looking at the wrong 68k processor: The daughterboard on the RESHA is just for TCP/IP.
The failing RAM test is the 68k on the IOC board.
Opened the cardcage and where this label greets you:
Visual inspection of the IOC revealed nothing of notice.
Changed the Lithium battery which is used for the RTC.
Gently reseated all socketed chips on the IOC.
Gently reseated all the other cards in the card cage.
Still fails RAM test.
The IOC Schematic manual mentions a low-level debugger, but it seems to require RAM test to pass before you can enter it.
ID-information on the IOC:
Our workshop area has been rearranged, the GIER computer moved and I could finally uncrate the R1000s400.
After a visual inspection, I did "the smoke-test" and can happily report that the smoke stayed inside.
Unfortunately, we don't get very far in the boot sequence:
R1000-400 IOC SELFTEST 1.3.2 512 KB memory ... * * * * * * * FAILED
This is 512KB DRAM memory on a small daughterboard on a CMC ENP100 VME board mounted on the RESHA board:
I have tried various obvious remedies, reseating connectors etc, but to no avail.
A few small details have to fall into place before I can start to power up the machine: Our new workshop area is done now, and the last missing bit is the rearranging the power-circuits.
In the meantime scanning of documentation progresses about a binder per week or so, and should be complete before summer.