11/04 Project

Henk Gooijen henk.gooijen at hotmail.com
Thu Dec 14 10:16:00 CST 2017

For a quick read of the most important information of the M9312, see

It contains some interesting side notes from Don (at the end)

Van: Noel Chiappa via cctalk<mailto:cctalk at classiccmp.org>
Verzonden: donderdag 14 december 2017 13:47
Aan: cctalk at classiccmp.org<mailto:cctalk at classiccmp.org>
CC: jnc at mercury.lcs.mit.edu<mailto:jnc at mercury.lcs.mit.edu>
Onderwerp: Re: 11/04 Project

    > From: John Welch

    > CLR
    > 765000
    > LAD
    > EXAM
    > 'Bus Err' light comes on.

Oooh, that's very interesting, and illuminative. The ROM isn't working (so
there's no way for the software console to work - its code is in that ROM).

So look at Section 1.5 of the Technical Manual


and make sure all the jumpers on the M9312 are as required. In particular,
jumper W-8 should be _out_.

If it's not, that would explain why the ROM at 765000 isn't resonding. If it's
in, that M9312 board probably has a problem.

Also, while we're at it, it's probably worth making sure the CPU will
run. Do this:

  777           (This is a 'branch .' instruction)
  EXAM          (Should display '777')
  CLR           (I think you can dispense with these
  LAD           two, but just to be safe...)
  'Run' light should come on
  'Run' light should go out, should display '0' (or maybe '2', I forget)

    > Do you know which color wire (red, clear, black) goes to which festoon
    > connector (TP1, TP2, TP3, TP4)?

I would leave them all disconnected for the moment; you don't need them. One
is the 'boot' switch on the console, and its ground. The other is the 'boot on
power on enable' (a duplicate of S1-2), and its ground. Since we're trying to
manually start the ROM console from the front console, they aren't needed for

I don't recall offhand which one connects to which - I will have to check.

    > Don't want to blow anything up.

Not sure it will harm anything if you connect things wrongly, but that's
not tested.


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