Having worked for DEC for a number of years I'm used to the odd logic
They do explain them in the manual. I don't use a CAD system but
something much more useful.
Visio. Define a DEC logic symbol once, add connection points in the
right places, drop as many copies as you need, join connection points
and print on A0 paper. Modify drawing as much as you like and print a
new copy each time.
Iv'e moved the boards back a bit and as soon as I get a few mins I'll
see if I can spot why it won't write to memory.
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org
] On Behalf Of Tony Duell
Sent: 01 April 2008 20:31
To: cctalk at classiccmp.org
Subject: Re: Looking for a M8330 or a couple of SN74194's
Its not test gear that's the problem its access to the board. My Tek
465 will trigger on single pulses with no problem.
However whilst it's recommended that the the first CPU board (the
8330) be in slot 2 (The front panel is in No1) its not mandatory. So I
can move the boards back a bit and get to the front of
All Omnius slots are the same, and in an 8/e backplane, AFAIK all slots
are plain Omnibus.
The only time the top connectors are used on the M8330 is if you have
the EAE board set installed, I think. If you do, take it out for the
moment (you don't need it when trying to sort out a timing generator
You can then put the M8330 in whatever slot you want.
An extender board is useful, but by no means essential :-).
Another trick that's worked for me in the past if I can't re-arrange the
boards and don't have an extneder is to solder a hnadful of wires to
useful testpoints on the board and put it back in the cardcage. Then
probee the free ends of the wires (make sure they don't short to
anything!). Normally 2 or 3 iterations of doing that will get me to the
Manual I have, (very good) Schematics also (Awful) so bad I may even
redraw at least the 8330. I have an A0 HP plotter so its easy to do
DEC scheamtics have the odd error on them (I've heard it claimed said
errors are deliberate, either to stop the machine being copied, or as
copyright traps on the diagrams themselves). They're also somewhat
unconventionally drawn (flip-flops may appear to have 4 outputs!), but
I've got used to them. I must say that if I need to re-draw a
sechematic, I use pen and paper, not a CAD system...