PDP-11/45

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Tue Dec 7 19:20:27 2004

>
> At long last I've decided I've gotten enough HP systems restored, so I'm
> turning my attention to one of my other systems that's been rescued but not
> restored - a PDP-11/45. Yes, I'm going over to the dark side ;)

Good luck!. My first 'serious' minicomputer was an 11/45, and it took me
several months to get it going. Now, there were many reasons for this :

1) I had little experience of such machines, I was learning a lot all the
time (which was good!).

2) I take things slowly and carefully

3) I had the printset, an instruction set listing, and not a lot else.
Figuring out things like grant continuity from those alone took some work!

4) I didn't have this list to turn to :-)

5) I am somewhat stupid!

Personally, I'd check the PSUs first (seriously, there are over 1000
chips in the the processor alone, you don't want to wipe them all out in
one go!). Then run a minimal configuration (you cna pull the floating
point processor boards without problem, don't pull the KW11-L line time
clock, since there's a grant link you'd have to wire-wrap back again,
also you can't pull the MMU unless you have the address buffer board that
goes in place of one of the MMU boards). But run the processor, MMU (if
you have it), some memory, and nothing else. Toggle in a simple program
on the panel, get it to run that. Then add more memory and peripherals.
Keep checking the PSU voltages -- I've had all sorts of problems caused
by one of them being low.

A few more things. Unless you're doing something seriously weird, you
want a M9200 jumper (it's electrtically an M920, but thinner!) between
slots 26AB and 27AB of the CPU backplane. Connectors C-F of slots 26, 27,
28 are normal SPC slots, you should put grant continuity cards in there
if you don't have peripherals. Slot 28AB is the Unibus out (of course),
put a terminator in there if you have no more backplanes. The front
terminator goes in 1AB. Slot 1E and 1F are for KM11 maintenance boards.
You need at least one of these IMHO!


> testing. I'd really like to convert the thing from core to semiconductor
> memory, and hopefully get an RL02 up on it.

The 'proper' semiconductor RAM that goes in the CPU backplane is hard to
find!. I put a normal MUD RAM card in an expansion backplane. Works fine
Adding the RL11 is no problem at all.

-tony
Received on Tue Dec 07 2004 - 19:20:27 GMT

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