PDP-11/34 & DG Nova-3

From: David Williams <dlw_at_neosoft.com>
Date: Mon Feb 16 16:30:41 1998

On 17 Feb 98 at 1:49, Tony Duell wrote:
> >
> > What should be the next step in restoring these?
>
> You mean apart from finding some cards for the Nova?

Yes, I suspect that is going to be the tricky part of restoring the
Nova. Still it was only $10 for the system and the plug box. I was
thinking of trying to mount it in the same rack as the -11.

> Well, what I would do (briefly - I'll give you more info later when
> I'm less tired) is :

> 1) Check the PSU in the 11/34 CPU. It's probably fine,
> but you don't want to ruin all your boards

How should I check the power supply? I know that many people here
say you should always do this but with the small cheap micros I've
picked up so far I haven't bothered.

> 2) Get the PDP11 CPU working and talking to a terminal

What I need to determine is what type of terminal. I was thinking of
using my laptop with a VT100 emulator if I can connect up to one of
the serial ports listed below. The system is up at my office since I
don't have room at home at the moment and taking the laptop up there
is easier than digging a terminal out of my storage place.

> 3) Sort out the RK05 - if it needs it.
> 4) Hopefully there's some kind of OS on one of those
> RK05 packs. Boot it

I hope so too. None of them are labeled. I have some DEC floppy
drives which came with a Tandy Color Computer. Someone interfaced
them to the Coco and used them with OS-9. I have a bunch of Coco
OS-9 disks labeled as RX50 format. Anyway, one set of the drives is
in a dual drive box labeled RX180AB and the other is a Rainbow style
drive mounted in half of a Xerox enclosure. Could these be used on
the -11 and what type of interface should I look for? Seems to me it
would be easier to get software to the machine if I could use the
floppies.

> 5) Enjoy the machine.

This is the part I'm really looking forward to.

> No, there should be a top cover on the RK05. You can run the drive
> without it (e.g. for servicing), but it's best to keep as much dust
> off the heads as possible.

That's what I thought. Any idea where to locate a cover for it?
Maybe I can check with the scrapper I picked it up from. I also have
two RK05 drives in storage which came with parts of a couple of
PDP-8s I picked up recently. I may take those up there as well.

> > 11/34 itself. It has the octal front panel and decaying foam in
> > front. It also contains the follow boards from left to right looking
> > towards to back of the system:
> >
> >From memory, what you have is :
>
> > M7257
> > M7256
> > M7255
> > M7254
>
> Those 4 boards are the controller for the RK05. They fit into a
> special 4-slot backplane, as does the white ribbon cable from the
> RK05. What's in the slot _behind_ the M7257? There should be a
> terminator (either an M9302 or an M930) there.

I'll have to check in the morning when I get into the office.

> > M9202
>
> Unibus connector to link the backplanes
>
> > H-228B
> > H-222A
> > H-222A
>
> Core memory, I think
>
> > M7850
>
> Memory parity check board
>
> > M9202
>
> Another bus connector
>
> > M7856
>
> Serial port/line time clock. You have 2 of these - one is probably
> the console port.
>
> > M7258
>
> I can't remember. Is there anything written in the copper etch?

The "Field Guide" I found lists this as a printer controller.

> > M7856
>
> Another serial port.
>
> > M7814
>
> Again, I've forgotten this one.

This one was listed as a "DZ-11 U 8-line 20ma data MUX, 50 to
100 Kbaud". Console connection? If so, what about the serial ports
above? This would count out my laptop right?

>
> > M7859 (Behind this is a M9301YF)
>
> M7859 is the interface for the octal keypad. Look carefully at this
> board - there's an 18 pin chip on it that's often in a gold-topped
> package. It's an 8008 CPU.

Wow, now that's cool. I'll have to look for that one.

>
> M9301 contains the boot roms and a trivial machine code monitor (a
> version of console-ODT) that lets you edit memory from the console
> terminal without using the keypad
>
> > M8265
> > M8266
>
> The CPU. One board is the data path (ALUs, registers, etc), the
> other is the control (microcode ROMs + sequencer).
>
> Hope the above helps.

Yes it does. Thanks!

>
> -tony
>
>
-----
David Williams - Computer Packrat
dlw_at_neosoft.com
http://www.neosoft.com/~dlw
Received on Mon Feb 16 1998 - 16:30:41 GMT

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