Repairing an 800XL Keyboard Cable?

[+Larry]

I have an 800XL keyboard that has a delaminated, damaged end, such that the individual contacts are no longer functional. This is not a cable with chemically deposited traces -- these are individual flat "wires" that are laminated within a tough plastic sheath. The cable is plenty long -- I just need to decide how to expose the contacts on one side.

 

I've given this some thought, and the alternatives that I see are

1) HEAT to break down the plastic bonds and lamination -- soldering iron or such with lower than normal temp.

2) Chemical attack with some type of powerful solvent or paint stripper.

3) Surface abrasion on one side with something like an emery board to wear away the plastic on that side sufficient to expose the contacts.

 

Anyone ever tackled one of these before? Any other ideas?

 

Thanks,

Larry

[Rybags]

I think I know the type you mean.

 

I wonder, would cutting the excess between the wires then using wire strippers work?

Of course that's probably only good if you're wanting to reattach to the keyboard.

 

For the system end - unsure. Maybe the abrasion technique would be best.

 

Or better cure all-round - change the whole thing to use a ribbon cable as per older PC HDDs. Whole bunch of work there though.

[russg]

I have an 800XL keyboard that has a delaminated, damaged end, such that the individual contacts are no longer functional. This is not a cable with chemically deposited traces -- these are individual flat "wires" that are laminated within a tough plastic sheath. The cable is plenty long -- I just need to decide how to expose the contacts on one side.

 

I've given this some thought, and the alternatives that I see are

1) HEAT to break down the plastic bonds and lamination -- soldering iron or such with lower than normal temp.

2) Chemical attack with some type of powerful solvent or paint stripper.

3) Surface abrasion on one side with something like an emery board to wear away the plastic on that side sufficient to expose the contacts.

 

Anyone ever tackled one of these before? Any other ideas?

 

Thanks,

Larry

Can you just cut off the end of the ribbon and peel back the layer to expose the contacts?

[+Larry]

Hi Russ-

 

No, can't be done. The very tough plastic encapsulates the wire leads. No practical way to split the plastic coating.

 

-Larry

[Rybags]

Thinking some more, heat might be worth a shot.

[+Larry]

And the "winner" is...

 

None of the above. Abrasion does work , but the plastic just keeps balling up. Heat also works, but has similar problems. I finally tried using an X-Acto knife with a small 45-degree blade and it worked pretty well. I was able to scrape the plastic above the wires in a quite precise manner. But some of the keys no longer work, and I can't see why. Bummer!

 

A constant problem is that a few of the wire ends de-laminate from the backing, making them prone to damage when inserting the cable.

 

I'm not giving up, but need to rethink alternatives. I know that some early 600XL's came with a small cable adapter that I might be able to use.

 

-Larry

[+Larry]

FIXED! The final repair was to scrape the plastic off with an X-Acto hobby knife and then carefully clean off any remaining plastic with some fine steel wool. (Always stroking the cable toward the cut end to avoid pulling up the wires.) After that, if carefully inserted, it should be good, but if it is going to be removed/re-inserted more than once, then you need the adapter also previously mentioned.

 

-Larry