VAX 11/730 quickie

Mike Ross tmfdmike at
Fri Feb 19 17:22:16 CST 2016

Just started working on mine - been a back-burnered project for a long
time. Unfortunately all the cables were cut when it was dismantled; I
was lucky to grab just the CPU.

Got it powered up ok - no drama there. I faked cables to the port on
the WCS which drives the console and hooked up my trust VT220 at 2400
baud. Nada. No self-test prompt; no ROM> prompt.

Maybe I've messed up the faked console cable; I'll check - already
tried obvious things like making sure Rx & Tx were crossed (it's a
three wire cable according to the schematics - Rx Tx Gnd; no flow
control). But I'd like to know more about the assorted LEDs on the CPU
boards; maybe there's a clue there if it's not getting far enough into
the self-test to display console output. There's a fair few LEDs on
the M8391. But the doc I've looked through on Bitsavers doesn't seem
to document their meanings and interpretations. Can anyone help on
that point?

Hopefully this link works:


'No greater love hath a man than he lay down his life for his brother.
Not for millions, not for glory, not for fame.
For one person, in the dark, where no one will ever know or see.'

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