Commodore 64-sx Keyboard getting stuck?

[Tony Duell]

> 
> On 7/11/05, Louis Florit <florit at gmail.com> wrote:
> > Hi, I pulled out my 64-sx out of the box it's been stored with in
> > anticipation of getting my JiffyDos upgrade installed into it.  To my
> > dismay, when I plugged it all in and powered it on, the keyboard
> > wouldn't work properly.  Any of the keys have to be pressed multiple
> > times (3 to 10 times) in order to get the character to show up on
> > screen.
> > 
> > Any suggested remedies?  I'm wondering if the keyboard contacts are
> > just a little dirty and need a little cleaning, but I wanted to check
> > with the gurus before prying it apart.
> 
> Unfortunately, the SX-64 keyboard is made entirely differently than
> PET and C-64 keyboards... the SX keyboard is layers of mylar with

Bletch!!!

> printed traces.  The traces have been known to oxidize over time,
> rendering the keyboard inert.  You can try to be as careful as you
> can, but I have seen plenty of dead keyboards from attempts to repair,
> and have never seen a successfully repaired keyboard.  If you manage
> to work out a successful technique, please share it with us.  I myself
> have two SX-64s, two good keyboards and two dead keyboards (neither by
> my hand).

Sounds like the infernal DEC LK201... I've never managed to repair one of 
those either. 

If it's screwed together, or if you can use screws to reasssemble it 
after cutting off the heat-stakes (the IBM PC/AT 101-key keyboard is built 
this way), then take it apart, clean the contact layers with propan-2-ol. 
and pray :-). Most of these keybaords are heat-staked and you can't use 
screws (noting to tap into), so you are pretty much stuck.

> 
> One possible solution would be to wire up an appropriate switch matrix
> to a the correct DB25 pinout and completely replace the native SX-64
> keyboard.  It would be functional, but not as portable.  I don't want

How similar is the matrix to the C64 keyboard?

> to say there's zero chance of repairing the original keyboard, but it
> would be an accomplishment to do so.
> 
> -ethan
> 
> 

-tony