
Restoring a DEC 340 Monitor - larsbrinkhoff
http://engblg.livingcomputers.org/index.php/2018/06/07/the-dec-340-monitor/
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crispyambulance
Damn, that circular screen reminds me of the computer on the old Star Trek
episode "Assignment: Earth".

This is where the Enterprise goes back in time to a 1960's Apollo launch. They
then encounter a man from the distant future, "Gary Seven", who also traveled
back in time.

Gary Seven had a computer that looked like DEC 340
([https://www.pinterest.com/will5967/sci-fi-star-trek-
tos-s02e...](https://www.pinterest.com/will5967/sci-fi-star-trek-
tos-s02e2655-assignment-earth/)).

This episode also has a very young Teri Garr as his secretary and a cat that
turns into a woman with cat ears.

~~~
madengr
The M5 developed by Dr. Daystrom had the same circular display.

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peatmoss
For those unfamiliar with the organization at work here, the Living Computer
Museum is a gem of a museum located just south of Downtown Seattle. It’s chock
full of amazing historical computers that you can actually use for the most
part.

I’ve been to the museum probably a half dozen times since I discovered it two
or three years ago. Each time I come back there’s something new on display.
Highly recommended.

~~~
slededit
Its really sad they don't have any that allow you to use a front panel. Even
their IMSAI 8080 has a plexiglass cover over the switches.

I understand why they do it, but I think front panel computing is something
that will be lost without letting a new generation experience it. Its a much
more direct way to experience the machine.

Other than that complaint it truly is a great museum. They even have a Xerox
Alto you can play with.

~~~
peatmoss
I wonder if a front panel could be developed to work in conjunction with an
emulator. As it was explained to me, the few systems that you can’t play with
are mostly because they’re easy to mess up and hard to reset.

It sounds like you have some expertise in front panel operations? If you have
the time and inclination, maybe you could offer to help them out. At the very
least, an email explaining your thoughts might inspire one of their engineers
to create something.

~~~
slededit
There are cheaper kit clones of the Altair and others with front panel
switches.

I just find it weird that they don't let you touch the one thing that can't be
emulated well, given the mission of the museum.

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rbanffy
It's a different beast, but I would love to know how the CDC-6600 dual screen
console was controlled. I have no idea whether it had internal memory to keep
a character-based display list or whether all tracing was controlled from the
host computer. Does anyone have anything on it?

~~~
speps
[http://ed-thelen.org/comp-hist/vs-cdc-6600.html#S-P-Hardware](http://ed-
thelen.org/comp-hist/vs-cdc-6600.html#S-P-Hardware)

Search for "Characters on the monitor", seems to be software based vector
display.

~~~
rbanffy
In case someone else is interesting in the font used for the console,
[http://bitsavers.trailing-
edge.com/pdf/cdc/cyber/cyber_70/fi...](http://bitsavers.trailing-
edge.com/pdf/cdc/cyber/cyber_70/fieldEngr/60125000C_6602_6603_6622_6681_6682_Data_Channel_Diagrams_Dec65.pdf)
has that information. I spent a long time looking for it (and I think I read
all the documents on the site, EXCEPT FOR THIS ONE # _@_ ⁾

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2sk21
I misread the title and initially thought that it would be about the DEC
VT340, a graphics terminal that I used a lot back in the 80s. Interesting that
product numbers were reused.

~~~
larsbrinkhoff
I made a more detailed title, but someone changed it to the title of the blog
post.

It's not a VT series terminal, but a Type 340 CRT vector display. The "Type"
designations were used with early DEC products.

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varjag
Quite likely Germanium transistors can be replaced with their relatively
inexpensive Soviet NOS copies. Many types were manufactured well into 1990s.

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devindotcom
This is a great museum, I've been a bunch. They really have an amazing
collection.

Last I went I actually talked with Keith and some other of their people who
are restoring all kinds of stuff. They're very interesting people to talk to.
I highly recommend visiting and asking around if you're in downtown Seattle
some time with a free afternoon.

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Posibyte
Is there a reason a Silicon transistor/diode wouldn't work here? I'm assuming
it either has something to do with voltage sensitivity or frequency, but older
computers like this tended to use fairly high (TTL) logic for signaling.

~~~
tsomctl
> Diodes this old when put on a curve tracer can sometimes look more like a
> resistor than a diode.

~~~
Posibyte
Ah, ok I get it now. My eyes somehow completely skipped that paragraph.

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larsbrinkhoff
Looking forward to see these PDP-6 or PDP-10 applications:

* TECO

* DDT

* Spacewar

* Dazzle Dart

* Game of Life

* MacHack VI

* Stanford University Drawing System

* SHRDLU

* Logo turtle graphics

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fernly
You can see Spacewar (and if you get into the demo room well before the demo
starts, even play it) at the CHM in Mountain View, CA. The PDP-1 demo (with
music synthesis and spacewar) is on first and third Saturdays, 2:30 and 3:15p
[1]. But the demo room is ridiculously small and crowded, so be early.

[1]
[http://www.computerhistory.org/hours/](http://www.computerhistory.org/hours/)

~~~
larsbrinkhoff
It'd be interesting to compare PDP-1 and PDP-10 Spacewar side by side.

