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Thread: CIT-101 terminal

  1. #11

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    You can usually boost tube outputs by pushing the heater a little harder. Not particularly good engineering practice I daresay but tube heaters are pretty tough and underrun. Used to be common practice with old b/w TV sets when I helped out in the shop. Not yesterday though!

  2. #12

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    If the ion trap magnet is separate from the yoke, you can flip the tube over so that the burned area is on the right instead of the left.
    Dwight

  3. #13
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    Today, I found some time to work on the CIT-101. I've been talking to Ryu. He has done a project to build a USB keyboard that works with a VT-100 monitor. This encouraged me to attempt to connect a keyboard to my CIT-101. I hope to duplicate his project with a USB keyboard to see if it will work with the CIT-101. Then make some changes to see if the Arduino will work between the CIT-101 and my RCA parallel keyboard.

    A little more progress was made today. I modified the Arduino program to scan through all the keycode address and to vary the keycode timing to the CIT-101. At first there was nothing. But the local rocket scientist didn't remember that the keyboard input results in an output to the RS232 port and not the screen. After making a loop back plug, the CIT-101 monitor came alive with a bunch of character on screen and it would occasionally stop on a Setup Menu screen.

    20190219_132840.jpg

    You may notice that the CRT is rather bright. I don't know why the 'keyboard error' message was so dim and the regular display is not. Maybe something in the NVR needs to set so that this is not the case. The CRT is amber and have two levels of intensity. I will not need all of those good tips on how to get around a weak tube. I'll keep them in mind should I need them.

    So, now I'm really optimistic that this monitor will work with a keyboard. Now I have to wait for parts to arrive and be assembled to see if the USB keyboard can be used. Thanks for the help, Mike.

  4. #14
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    Nice progress!
    Torfinn

  5. #15

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    I'm on the wrong side of the pond but I happen to have a spare CIT-101 keyboard that I got with some DEC VTs; thinking about it I actually have two.

    Sounds like you're making good progress though!
    www.binarydinosaurs.co.uk - UK home computer history
    Where RIFA capacitors come to die
    facebook.com/binarydinosaurs

  6. #16
    Join Date
    Dec 2013
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    Witchy, it sure would be nice to have a working keyboard to know whether or not the monitor is in good shape. I'm still unsure. My daughter purchased a new home and I've been helping with the move and fixing the house, so my computer trouble shooting has diminished to near nothing. Although last night I made a short attempt and this time the monitor displayed something new;

    "copyright 1980 by International Magic" I wonder where that came from?

    Ryu has also send me his VT100 keyboard project hardware and I recieved the parts to make my own, but that may have to wait. Anyway, we'll see. Thanks Mike

    Which pond? Lake Michigan?

  7. #17
    Join Date
    Sep 2006
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    Silicon Valley
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    Quote Originally Posted by Witchy View Post
    I'm on the wrong side of the pond but I happen to have a spare CIT-101 keyboard that I got with some DEC VTs; thinking about it I actually have two.

    Sounds like you're making good progress though!
    could you take some pictures of the insides, and dump the firmware if possible?

  8. #18

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    Quote Originally Posted by Mike_Z
    Which pond? Lake Michigan?
    Sadly the Atlantic Ocean, I'm in the UK.

    Quote Originally Posted by Al-Kossow
    could you take some pictures of the insides, and dump the firmware if possible?
    Yep no problem, I think I already dumped the firmware because I didn't know what the keyboards were from. I'll do it tonight.
    www.binarydinosaurs.co.uk - UK home computer history
    Where RIFA capacitors come to die
    facebook.com/binarydinosaurs

  9. #19
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    Jan 2010
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    Probably still worth shipping from the UK, if you want an original keyboard.

  10. #20
    Join Date
    Dec 2013
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    Near Milwaukee Wisconsin
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    Witchy, Forgive me, but I didn't read into your post that you were willing to part with a keyboard. If you are I'm interested. Thanks Mike

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