Repair Keyboard Rubber Contacts?

[Bouncy nugget]

Have you tried contacting the manufacturer and inquiring about buying a replacement keypad?

Not yet. Are you sure it's the contact rubber and not the circuit board?

 

[shrtrnd]

No, I don't know if it's the circuit board. And I don't know if the problem is actually electronic components connected
to that circuit board either. What I assume, from your description that you can 'penci'l over the board and make the contacts work for a while, is that the keyboard itself is the problem in one way or another.
You talked about the 'black' trace on the board for contacts. Are they like the black contact trace in Harald Kapp's photo?
If so, I don't know if you have black carbon covering a copper trace on the board, or if you JUST have carbon AS the trace on that board. If the squiggly line trace on the board is JUST carbon, and you say when you clean that trace it is rubbing off all over the board, then yeah, it would be the black trace on the board that is the problem.
If you can't get parts for your unit, you might consider using your conductive pen (OR A REPAIR KIT DESIGNED FOR THIS), to try to replace the problem trace pattern on the board.
The best way to identify this problem, is to jumper the trace pattern on the board for each key, to make electrical contact and verify that, that particular switch contact is closed (activated), and that you just need to figure-out the best way to ensure contact between the squiggly-line trace is made when the rubber push-button is depressed.
We're trying to help, but we don't even have a picture of what you're seeing there.
We only have what you tell us to go by, and may bark up the wrong tree if we misunderstand your problem.

 

[Bouncy nugget]

We're trying to help, but we don't even have a picture of what you're seeing there.
We only have what you tell us to go by, and may bark up the wrong tree if we misunderstand your problem.

I uploaded the photo that Harald Kapp showed. I put the conductive pen on the rubber pads under the contact strip (where Harald put the red dots) but it made no difference, all working notes still work and malfunctioning notes still malfunction. What i had originally noticed is if i rubbed my finger along a working 'carbon trace' on the circuit board (as seen on the right side of the photo) it then malfunctions. I think there is some kind of conductive grease or something on the circuit board that has worn off, and that is why scribbling pencil on it helps.

I have no idea at all though because i have no knowledge of these things except what i've learned just recently while messing around with this keyboard. If you figure out what the problem is, i'd like to know specifically what substance to purchase and how i should apply to the traces, so there are no mistakes.

Thanks!

 

[Bouncy nugget]

Anyone?

 

[shrtrnd]

I don't have anything new for you. Harald Kapp gave you what I thought was some pretty good information that I didn't even know about. I'm apparently too unfamiliar with the construction of your keyboard to offer anything useful. If I was you, I'd consider trying Harald Kapp's suggestions, and/or contact the manufacturer of your keyboard for advice or replacement they may be able to sell you. It sounds to me like you've tried everything you could with what you have available on-hand.

 

[Bouncy nugget]

The only thing i haven't tried is putting some conductive substance on the carbon trace on the circuit board other than led pencil, which works for a short time. I do not know what substance it is that i require though.

 

[shrtrnd]

Go back and re-read Harald's first post to you in this thread.
He linked you to what you asked for above.