The PDP11/04 has landed..

Mattis Lind mattislind at
Mon Feb 8 02:11:10 CST 2016

2016-02-07 18:55 GMT+01:00 Jos Dreesen <jdr_use at>:

> Yesterday I picked up the PDP11/04 that Jay mentioned a few days ago.
> Less than 15 miles from home  !
> The machine spend its early days as a processor in chemical analysis
> apparatus, and was subsequently bought by the employee using it.
> Before he could make use of it better, more powerful, easier to use
> machines came along and the -11 spend the next 30 years in a garage.
> The -04 is an entry level machine, and the cards inside match this :
>     M7263 KD11 CPU
> 2 x M7264 16K DRAM cards

No, it cannot be M7264. I guess that it is a M7847 MS11-E board. M7264 is
the quad KD11 / LSI-11 CPU board.

>     M7856 DL11 SLU/RTC
>     M7846 RX01 controller
> 2 x M7814 DZ11-F
> and of course the M9301, M9302 and M9202.
> Alas it has just the simple 2-switch frontpanel.
> The machine also had the battery backup option, and the lead/acid
> batteries will celebrate their 40th birthday next year !
> Better not try to charge them....
> Overall the machine is in very good condition, both CPU and RX01, and it
> is packed in a very nice half-height rack with the red PDP11 bezel at the
> top.
> Pictures next week when the machine is cleaned and reassembled,
> restoration is to start next winter, after a house move which will nearly
> double working area for the hobby.

This is a really nice, simple little system. It will happily run RT11 from
from the floppies. The lack of programmer console is a little bit annoying
when debugging it but when it is operating properly the console emulator
will be enough for most purposes. The M9301 is a rather fixed compared with
the M9312 were you can install your own boot ROMs of your own choice. For
example useful things like to have it to boot from TU58 or MSCP devices.

I guess that the CPU box is in a BA11-K box. They are incredibly heavy, but
much much easier to use compared with the BA11-L which is a pain to work
The modularity of the BA11-K is also very nice. I haven't had much trouble
with the PSU modules in the BA11-Ks I have worked with. The lightbulb of
course but other than that they were fine.

Good luck and congratulations to a nice system!

> Many thanks to Roland for preserving the machine, and to Jay for acting as
> an interface !
> Jos

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