Revive 11/34

Noel Chiappa jnc at
Sat Dec 9 07:56:52 CST 2017

    > From: John Welch

    > Any suggestions as to what to try first? 

I would _definitely_ start by pulling _all_ the cards you can, to get down to
the simplest possible configuration. Once that works, start adding things
back in, one at a time.

If that configuration doesn't work, first try the obvious things (clean and
re-seat, check voltages, etc). If that doesn't get it running, it's time for
a oscilloscope or logic analyzer. (We can help you through that.)

So I'd start with the CPU (M8266/M8265), front-terminator/bootstrap ROM
(M9312), the front console card (M7859), and rear-terminator (M9302) (which
you need for grant turnaround, see next paragraph). That's it.

IIRC, the /34 will complain if the bus grant chain is not complete (I really
need to look at the prints/ucode to understand why this is so - other -11's
will run basic functionality fine with an interrupted grant chain), so plug in
grant jumpers in every unused slot. Also, check the backplane, to see which
slots have had their NPG jumpers pulled, and either i) use a G7273 jumper (the
dual boards which contain an NPG jumper as well as the BR jumpers) in those
slots, or replace the jumpers.

I _think_ the machine will be OK without any memory, but I don't have a
running 11/34 to test that on. (Only my /04 is running at the moment.) I can
plug my /34 cards in and try it, if that will help. But maybe someone else
knows. So maybe you'd have to add a memory card, but that would _definitely_
be the biggest configuration I'd try until the basic machine is working.

You can examine the MMU registers in the CPU to check that the bus/console etc
are working - first read, then write. And IIRC the CPU general registers are
accessible from the bus too - I know they are in the -11/04 (which uses the
same front console).


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