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TYPE 340 round display question

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R Clark

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Apr 5, 2025, 8:20:06 PMApr 5
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Looking at pictures on the web, I see  hole/knob/switch or something in the lower left corner of the display panel.  Wondering what that was if anything. I freeCad'ed a simple box and added a small hole in that corner.  I can drill out to size as needed (or re-cut) after I laser cut the pieces. You see, I bought a 5" hdmi round touch screen from Waveshare to hopefully sort-of recreate the 340 display for fun.  Since the PiDP-10 is on a shelf and the RPI-5 hdmi connectors are being unused...  Anyway, see where project goes...  This hobby is addicting...



Tim Radde

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Apr 5, 2025, 8:29:17 PMApr 5
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I can't find a decent picture on the web that shows this. Can you provide one?

Stephen Jones

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Apr 5, 2025, 8:32:41 PMApr 5
to Tim Radde, PiDP-10
Courtesy of SDF Vintage Systems.



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david avery

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Apr 5, 2025, 8:40:18 PMApr 5
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pretty sure that is the display brightness control knob

R Clark

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Apr 6, 2025, 10:32:13 AMApr 6
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Thanks for the hi-res picture!!!  I couldn't find a good one on the web either.  

So a smooth silver control knob with a black center to control the brightness.  

Stephen Jones

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Apr 6, 2025, 6:23:31 PMApr 6
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On both Type 340s here the potentiometer on the bottom left adjusts the gain control for the light pen.
Brightness and other adjustments are done through the PM calibration procedure.

Stephen Jones

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Apr 6, 2025, 6:26:07 PMApr 6
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Your welcome, also this video of the Type 340 on our PDP-7 might be useful as well:



On Sun, Apr 6, 2025 at 7:32 AM R Clark <rbclar...@gmail.com> wrote:

pbi...@gmail.com

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Apr 7, 2025, 12:04:14 AMApr 7
to Stephen Jones, R Clark, PiDP-10

Pretty interesting multi-media presentation :-}.  Thank you for sharing it.

 

  1. What phosphor does the Type 340 use?
  2. What is the source of the audio?
  3. Is the source code available for study?

 

It would be interesting to reproduce these outputs in other environments!

 

From: pid...@googlegroups.com <pid...@googlegroups.com> On Behalf Of Stephen Jones
Sent: Sunday, April 6, 2025 6:26 PM
To: R Clark <rbclar...@gmail.com>
Cc: PiDP-10 <pid...@googlegroups.com>
Subject: Re: [pidp-10] Re: TYPE 340 round display question

 

Your welcome, also this video of the Type 340 on our PDP-7 might be useful as well:

 

 

-----

Lars Brinkhoff

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Apr 7, 2025, 12:59:51 AMApr 7
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  1. What phosphor does the Type 340 use?

P7 

Stephen Jones

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Apr 7, 2025, 1:06:50 AMApr 7
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P7 phosphors. The audio was captured by holding a yaesu uv8dr near various places around the controller backplane tuned out of the AM broadcast band. Both listings and more can be published on SDF’s git server soon! 

Both our Type 340s operate but we need to fabricate a controller to used the pictured one on our PDP-6.  More details on its analogue rebuild soon.

Lars Brinkhoff

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Apr 7, 2025, 1:21:33 AMApr 7
to Stephen Jones, pbi...@gmail.com, R Clark, PiDP-10
SMJ wrote:
Both our Type 340s operate but we need to fabricate a controller to used the pictured one on our PDP-6.  More details on its analogue rebuild soon.

Wow, you'll be able to demo SHRDLU in style!

Bradford Miller

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Apr 7, 2025, 10:05:40 AMApr 7
to Stephen Jones, PiDP-10
What is the panel that was cut off on the right of the picture?

> On Apr 5, 2025, at 8:32 PM, Stephen Jones <sdfp...@gmail.com> wrote:
>
> Courtesy of SDF Vintage Systems.
>
> <IMG_9400.jpeg>
>

Lars Brinkhoff

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Apr 7, 2025, 1:03:52 PMApr 7
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Bradford wrote:
What is the panel that was cut off on the right of the picture?

A PDP-8 "straight eight".

steve...@gmail.com

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Apr 7, 2025, 2:57:30 PMApr 7
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Photos of the "Classic 8" I used to own:
P1040003.JPG
P1040002.JPG
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