Refurbishing Vic-20 keyboard

[protek]

The keyboard in my Vic-20 requires a bit more determined keying with some keys. Can the key contacts be refreshened with isopropyl alcohol or are they just plain worn?

 

[fiat1100d]

The keyboard in my Vic-20 requires a bit more determined keying with some keys. Can the key contacts be refreshened with isopropyl alcohol or are they just plain worn?

I once refurbished a VIC-20-like keyboard (it actually was of an older CBM 8032-32B) by glueing with super glue small pieces of aluminium foil, the type used for cooking, on the rubber contact of the keys.
I suppose each key has a rubber contact which tend to worn out with time and then having a bad contact, not closing the track on PCB.

You can try with a limited number of keys for checking if this solution is ok for you, but it should be, only you will need to be patient if ALL the keys have this issue. Of course, trying some cleaning first won't hurt.

 

[protek]

Thanks! Have to find time to open up the keyboard.

 

[Merlin]

I've also used pencil graphite rubbed on the rubber pads to increase the conductivity and it works 100%. It might be worth trying this before the aluminium foil method.

I used to use graphite a lot to repair rubber keys contacts on calculators etc.

 

[protek]

Thanks, Merlin!

Had not thought about graphite. I've used it to overclock my AMD Duron processors.

 

[protek]

Tried to dismantle the Vic keyboard yesterday. Couldn't dismantle it all the way, since the shift lock switch is soldered into the keyboard membrane and I didn't have possibility to desolder it. I could however see, that it is not a rubber mat having conductive pads but instead there are independent shafts that have a sort of bridge, which will close the circuit on the membrane. From the side the brige looks like this: |_-_|.

Couldn't take a proper look due to not being able to detach the shift lock. Therefore I couldn't see if there was a conductive layer on those shafts. All the keys do work. Some just need a firmer keypress than others.

 

[UberFreak]

Usually cleaning the conducting pads is enough.
I renovated several keyboards using a special conductive black paint, which a friend gave me years ago.
Unfortunately, I cant remember how it was called & wasnt able to get another one

I've also seen, in a local electronics lab, special conductive stickers used to repair remote-control pads.
The guy who worked there refused to sell me the stickers or tell me where he got them, I tried several electronics shops without luck, but I'm not giving up!

 

[SkydivinGirl]

@protek

The C64 keyboard has the Shift Lock soldered just like the VIC-20 does. Before I knew how to de-solder them, I cut the metal wires then soldered the wires themselves back together. It would, of course, be better to remove them at the solder points though.

I always used Isopropryl Alcohol to clean the rubber feet contacts on the keys of my C64. You can also clean where the board that the feet push on to make a connection. This process always worked well for me, but it's been many years since I did it.

Good luck!

Heather

 

[Merlin]

@ Uberfreak

I reckon that the conductive paint that is used to repair circuit board tracks would probably work.

@ SdG

Mmmmm... Iso Propyl Alcohol.....:drool: Sorry, that's the inner chemist in me showing through.....

 

[SkydivinGirl]

LOL! Silly boy.

Heather