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View Full Version : 11/20 comes to visit



jackrubin
April 28th, 2011, 06:50 PM
I'm going through this machine for a friend. Voltages look good (on a meter, though I haven't put a scope on it yet) and first power up was smoke free. At some point, the KL-11 tty interface was modified to a more generic i/o card so I'm looking for an M780 to restore tty capability but otherwise looks pretty good. Fun ahead!

https://picasaweb.google.com/jack99rubin/20110423PDP_1120?feat=email#

Jack

RSX11M+
April 28th, 2011, 07:33 PM
Nice pics there Jack... thanks. I can sniff the box from here!

Doubt I'll have anything on that M780, but I will look. It's not impossible.

pontus
April 28th, 2011, 11:02 PM
Nice looking 11/20. Do you have a plan for the missing front panel buttons?

stargeezer
April 29th, 2011, 03:27 AM
Nice. Really nice. I have a friend who has a 20 that's been sitting untouched in his basement for 25 years. It had power supply problems so he shelved it. He has quite a nice collection that is awaiting his retirement I believe.

GilesGoat
April 29th, 2011, 03:34 AM
I just want to say "It's really nice to see so much love" ..

I just had a quick VERY SAD conversation with a friend in UK that was telling me about "DEC equipment" in a place in UK that is going to be thrashed and they don't want/allow anyone to have/touch it ( NO IDEA WHY ) .. unfortunately a very common thing to happen.

I swear no kidding when I hear stuff like that it breaks my heart.

jackrubin
April 29th, 2011, 02:55 PM
There _may_ be a box of spare parts for this machine, possibly with spare switch handles, but that's yet to be seen. At least the current switches all seem to work, even those with missing paddles, though they're not much fun to operate in that mode.

My more immediate goal is to rig up a tty console, either by finding an M780 or using an M7800 in current loop mode. Even better would be finding a G8000 so I could use the M7800 in EIA/RS-232 mode. With a console, I can start running diagnostics and get a better idea of the machine's condition.

RSX11M+
April 29th, 2011, 05:49 PM
...I just had a quick VERY SAD conversation with a friend in UK that was telling me about "DEC equipment" in a place in UK that is going to be thrashed and they don't want/allow anyone to have/touch it ( NO IDEA WHY ) .. unfortunately a very common thing to happen...
Sounds like it was used to hold or process secrets. It's a common military requirement in the states for certain systems, especially older ones that were not engineered to be rendered "safe". I can recall the procedure for "inerting" an Intel Bubble Memory module... it involved a .45 cal pistol! No kidding.

However, most of that equipment ceased to be held so long ago, that it was all disposed of in the past.

If you really want to cry, do some research into the CPU for the SafeGuard system (http://srmsc.org/pdf/005213p0.pdf). I can tell you how it was disposed of, and it will curl your hair. A detailed history is here (http://srmsc.org/pdf/004438p0.pdf), if you have the stomach for it.


There _may_ be a box of spare parts for this machine, possibly with spare switch handles, but that's yet to be seen. At least the current switches all seem to work, even those with missing paddles, though they're not much fun to operate in that mode...

...My more immediate goal is to rig up a tty console, either by finding an M780 or using an M7800 in current loop mode. Even better would be finding a G8000 so I could use the M7800 in EIA/RS-232 mode. With a console, I can start running diagnostics and get a better idea of the machine's condition.
Hmmm... I rather like the old binary switch consoles. It's one of the "charms" I miss from the 11/70. But you're right, once I get to the XXDP stage, a serial console terminal is a must. I prefer my LA120. [ASR33 is too slow, and mine needs work]

RSX11M+
April 29th, 2011, 08:34 PM
There _may_ be a box of spare parts for this machine, possibly with spare switch handles...
I used to work in a shop that made Movie Models for Hollywood. Whenever we needed something like that we made a mold and poured plastic castings.

It was a little expensive to make the mold, but after that, many pretty good copies could be made. If there's enough call for these, I'd like to give it a try. Please let me know, and we'll arrange things.

Matching the colors will probably be the most difficult part.

GilesGoat
April 30th, 2011, 12:19 AM
Sounds like it was used to hold or process secrets. It's a common military requirement in the states for certain systems, especially older ones that were not engineered to be rendered "safe". I can recall the procedure for "inerting" an Intel Bubble Memory module... it involved a .45 cal pistol! No kidding.

No .. I got a better talk with that guy, in his words :



I can tell you exactly why it happens: under UK law, if a company transfers electrical equipment to someone else (even for free!) and it then breaks down/catches fire/runs amok and kills someone, the original company can be held liable for not disposing of it properly!

In practice you and I know the chances of anything bad happening are tiny, but it's used as an excuse for people in charge to take the path of least resistance - doing nothing :(

I'll stop thinking about it and move on .. I will only say that at times I managed to salvage some stuff from a skip when someone else was not watching because my heart was not taking it any more ..

RSX11M+
April 30th, 2011, 07:28 AM
... I will only say that at times I managed to salvage some stuff from a skip when someone else was not watching because my heart was not taking it any more ..
"Good on you".

No computer museums in the UK then? Pretty sad.