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Repairing an original KIM-1 keyboard

John Jones

New Member
Joined
May 31, 2021
Messages
6
Location
Hatfield, UK
Hello All

I've recently got myself an original KIM-1 – a Commodore-branded Rev G.

All is well, except the keyboard is unreliable.

The keys get progressively more unreliable and unresponsive from the top row to the bottom.

However, if I press down (quite firmly) below the bottom row – then, all the keys on the keyboard seem to work (the RS key works but never 'clicks' when pressed). I've attached a photo to make it clear what I mean by pressing down below the bottom row.

Pressing keyboard below bottom row.jpeg

I'm guessing the keys have become unresponsive with repeated use and that when pressed the contacts under the keys are not made, but that pressing down hard below the last row brings everything closer together and then the contacts are made on a keypress.

It seems obvious to me to dismantle the keyboard, find out what is going on inside, and try to bring the contacts back closer together. I assume the keyboard will come apart if I undo the screws below it on the reverse side of the motherboard (photo attached).

KIM-1 keyboard screws.jpeg

However, before I do, I wanted to see if anyone has ever done so, and, if so, are there any things (especially problems) I should be aware of? I've looked around online and on YouTube and can't find any examples at all of someone dismantling a KIM-1 keyboard.

Any feedback, advice, warnings, etc, would be gratefully received.

Thanks

John
 

MindWalker

Member
Joined
Jul 23, 2019
Messages
19
Location
Helsinki - Finland
I have a Rev G KIM-1 too :)

I remember cleaning the keyboard at one point and I found this picture from my archives.

It seems the key membrane connects to the PCB over four contacts right on the bottom row, you probably have a bad contact there. Cleaning and (carefully) tightening the screws might well cure it! Just be careful with the membrane.
 

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daver2

Veteran Member
Joined
Jun 19, 2012
Messages
6,801
Location
UK - Worcester
I am afraid I can’t help you as far as the KIM-1 keyboard is concerned, but (as this is your first post) I would just like to welcome you to VCFED (even though you appear to have joined a while ago).

Well done on your acquisition though.

A couple of guys in the States are knowledgeable experts on the KIM-1...

There you go, just beaten to the post!

Dave
 

John Jones

New Member
Joined
May 31, 2021
Messages
6
Location
Hatfield, UK
I have a Rev G KIM-1 too :)

I remember cleaning the keyboard at one point and I found this picture from my archives.

It seems the key membrane connects to the PCB over four contacts right on the bottom row, you probably have a bad contact there. Cleaning and (carefully) tightening the screws might well cure it! Just be careful with the membrane.
That's a great photo – many thanks for the advice too.
 

John Jones

New Member
Joined
May 31, 2021
Messages
6
Location
Hatfield, UK
I am afraid I can’t help you as far as the KIM-1 keyboard is concerned, but (as this is your first post) I would just like to welcome you to VCFED (even though you appear to have joined a while ago).

Well done on your acquisition though.

A couple of guys in the States are knowledgeable experts on the KIM-1...

There you go, just beaten to the post!

Dave
Many thanks for the welcome Dave.
 

John Jones

New Member
Joined
May 31, 2021
Messages
6
Location
Hatfield, UK
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