Last of My Terminal Keyboards

[OldIsNew]

I've finished up with the last of the five terminal keyboards I've somewhat randomly accumulated in recent months. This one is a Televideo 935 terminal board (at least that's what it says on the PCB). It has white linear Hi-Tek 725 Space Invader switches that are kind of cool I think.

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It's nice to be able to use these boards on my Windoze machine - I guess I'll just rotate though them for a while. I think the really fun part, however, was just the process of working on them!

[ohaimark]

Wow. Those rows and columns look very easy to trace. I wish every keyboard had a PCB layout like that.

[OldIsNew]

Wow. Those rows and columns look very easy to trace. I wish every keyboard had a PCB layout like that.

Yes, it's a nice matrix layout for a change! The Shift, Ctrl and Funct keys were a little oddly routed, but the Televideo folks seem to have made the effort to produce a pretty straight forward matrix which is definitely not the case for some other boards I've seen!

[chip chop]

Great series of posts OIN. Really great stuff, thanks for posting them.

[orihalcon]

Do you have a closeup of how you did the teensy wiring? I could trace out myself, but this would save me a lot of work if I ever get around to restoring my TV935!

[OldIsNew]

Do you have a closeup of how you did the teensy wiring?

Sure, happy to post. These are the matrix I traced out and then the corresponding pins on the main IC. I was too lazy to rearrange the matrix diagram so that the letters and numbers would line up in order on the IC pins.

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One minor note - when I wired the existing Caps Lock LED to the Teensy, I had to desolder a resistor to isolate the LED from the IC pads. Got lots of wonky key presses when I first hooked up the LED.

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[snacksthecat]

I was having a hard time tracing out the matrix myself. I soldered it up last night and this appears to be just what I needed!

Thanks so much for taking the time to post these details. This will be a huge help in converting the two Televideo boards I have

[OldIsNew]

I was having a hard time tracing out the matrix myself. I soldered it up last night and this appears to be just what I needed!

Thanks so much for taking the time to post these details. This will be a huge help in converting the two Televideo boards I have

I'm glad it was helpful! These are very cool boards, and it appears you've found an excellent stash of them!