DECstation 5000/240 specific notes

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This is the second fastest model in DEC's line-up of Mips-based workstations.
I got it via an eBay auction, at a decent price with regard to its rarety and the fact that it was fully loaded with RAM modules.
However, it gave me quite a bit of headache and took many hours to get it up and running. It stubbornly refused to boot into the console prompt, always stuck after the prcache test message, which puzzled me quite a bit since the box doesn't have a Prestoserve module. The rear side LEDs ( ooxx ooxo ) OTOH indicated something might be wrong with RAM or CPU module, according to the Operator's Guide. Removed/reinserted both several times, cleaned contacts etc, the usual voodoo magic. Didn't help. Finally I suspected the CPU module and asked a local reseller for a quote. Way too expensive, would have costed much more than the machine itself. So I gave up for the time being and let the box catch dust on its shelf for several months.
On second try I discovered the box had an inappropriate video card, a PMAGD-AA which is supposed not to run in Mips'en, although it gives a reasonable output on power-up. First I replaced it with a PMAG-C, then tried without any graphics, console only. Furthermore I tried spare RAM modules one after the other. Suddenly I got strange error messages, ending up with the console R> prompt. First I was scared the machine would require a console password, but a bit of googling gave me hints that possibly the NVR (not to be confused with the NVRAM module) was messed up and might need a reset. Followed the procedure described below, and voila! the box booted into console prompt (>>). Joy!
Maybe the wrong video card messed up the machine, no idea.

Pixx

DECstation 5000/240 front view DECstation 5000/240 inside DECstation 5000/240 rear view

RAM

The machine came filled with RAM to the brim. First I thought I was lucky to have a 15x32MB=480MB machine, however, I couldn't verify that due to the troubles described above. After this has been fixed the console told me there were only 8MB modules, with a 32MB one inbetween. Since this mixing is not supported by ULTRIX, I removed the large module, leaving 112MB, which isn't too bad after all. Those MS02 modules are next to impossible to obtain nowadays.

Bootable CD-ROM

Boots from RRD40.

Reset NVR

Symptom: after power-up the box doesn't boot into console prompt but stucks at R>.
Cure: reset NVR (described also in the DECstation/DECsystem 5000 Model 200 Series Maintenance Guide, chapter 2 )
  1. Short cut the clear-NVR jumper. On a 240 it is located on the MoBo close to the PSU's middle fan, with a 4-pin connector close to it.
  2. Power on and wait until the normal console prompt appears.
  3. Power off and remove the short cut. The system should work normal now.
Last updated: 23-Apr-2010, M.Kraemer