PDP-11/05 restoration project - anyone has a M7810 or M781?

Jay Jaeger cube1 at charter.net
Sun Sep 27 23:39:26 CDT 2015

On 9/27/2015 2:54 PM, Mattis Lind wrote:

> Hello!
> I have started to work slowly with the PDP-11/05 I received a year ago. It
> is the big BA11-D chassis type machine. The power supply is now fixed and
> working fine. A few smaller capacitors were leaking. But also one of the
> big input filtering capacitors was bad and had to be replaced.
> The front panel have been cleaned and checked. The next step is to start
> looking into the the CPU itself. Unfortunately one of the CPU boards are
> marked "faulty" so there are certainly work to be done.
> The plan is to get it to work with the 8kW core memory, M7800 connected to
> a good old teletype and PC05 paper-tape reader / punch and then run paper
> tape BASIC on it or other paper tape software.
> The problem is that I am lacking in the M7810 board. Since I do have a M105
> and M7821 a M781 could do as well.
> Does anyone has a M7810 or M781 to sell?

My inventory says I have one (it is the interface to a paper tape unit,
of course).  If I have at least 2 more in other machines, then I could
part with one - and I expect that I have at least 3 or 4 in machines.
The one I have in inventory is untested.  I will check on that tomorrow,
and get back to you on that situation directly.

Note that DEC had two paper tape units had different interfaces,
depending upon what they were used with.  For the PC11 card to interface
to it, it needs to be a PC11 or a PC05 with the right cards in it.

> http://www.datormuseum.se/computers/digital-equipment-corporation/pdp-11-05
> BTW. Does anyone have a BA11-D chassis and could help me take a photo of
> the top and bottom covers? Those are missing on my machine and it seems
> impossible find a drawing for the BA11-D chassis itself. It is not in the
> PDP-11/05 Engineering Drawings which I already have.
> And if someone also have a G231 I would be interested because that would
> mean that the machine can be fully configured with 16 kWords!

I have several of those.  Most of those are also untested, but one has
been tested.

> /Mattis

In one of your other notes you mention Omnibus stuff.  I would love to
have an Omnibus paper tape interface, RK05 interface and/or RX01 interface.


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