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

[william degnan]

I have been through the ground up restoration of a full chassis version,
make sure the CPU is functioning correctly first. The best place to start:

http://www.psych.usyd.edu.au/pdp-11/hints.html

Try toggling in the  "Line Time Clock Interrupt Test" from 001000, returned
the expected value of 000104.

Here is a pdf of the cabling for tty console, if you have no current loop
device an rs232 converter will work.
http://vintagecomputer.net/teletype/asr33/M9970_TTY.pdf

See also
http://www.pdp-11.nl/pdp11-05/cpu/boards/m7260.html

echo characters toggle-in program
005000 CLR R0

105737 TSTB @#177560
177560
100375 BPL -3

105737 TSTB @#177564
177564
100375 BPL -3

113737 MOVB @#177562,@#177566
177562
177566

105737 TSTB @#177564
177564
100375 BPL -3

110037 MOVB R0,@#177566
177566

105737 TSTB @#177564
177564
100375 BPL -3

000756 BR -16





On Sun, Sep 27, 2015 at 4:47 PM, tony duell <ard at p850ug1.demon.co.uk> wrote:

> [Second serial port on a PDP11/05]
>
> > Curious: what if the built in one were
> > faulty, or if you wanted to use rs-232
> > instead of current loop?
>
> IIRC the 11/05S has a way to disable the built-in
> console port (fit a wire link on one of the boards?)
> the original 11/05 doesn't. There must be a way to do
> it by cutting/jumpering but it is a mess....
>
> Therefore, if the built-in port is faulty it is going to be
> a lot less work to fix it than to disable it and add a DL11
> Heck, the entire 11/05 CPU is only a couple of hundred ICs,
> the serial port is going to be a small fraction of those. It is
> not going to be hard to figure out.
>
> As for the physical interface, firstly the OP mentioned a
> teletype, which to me suggests current loop anyway. If
> you need RS232 then either pick up TTL level signals on
> the CPU board and add level shifters (very easy, but
> makes the machine not original) or make a current loop
> to RS232 interface (not exactly difficult either). I think
> both are less work than disabling the built-in port.
>
> -tony
>
>
>
> - John
>
>
>


-- 
Bill
vintagecomputer.net