> From: ricardorucier
>
> One of the keys weren't working, and I thought it was just out.
> Then I opened the top panel regarding another issue, and closed the
> panel, and then the key started working again, keep in mind, I didn't
> touch the key. I just assumed it was a fluke.
>
> A few years go by, and now, certain keys randomly don't play, then
> they play, then another one doesn't play. I'm looking for a pattern,
> but I'm not aware of the issue.
>
> For instance, if C1 key goes out for a second, I'll press C2, and C2
> plays just fine, so it's not a voice thing? Wouldn't that effect all
> of the octaves. The all of a sudden, C1 works fine for a while, then
> it's G1, and G2 is fine.
>
> Does cleaning the contacts effect if the MIDI signal triggers the
> sound or not, or is it just internal?
>
> If so, how do I go about cleaning the contacts, if not, how do I go
> about fixing this DIY?

If a synth channel is out, then playing a scale would cause a note to drop
out every sixth note (fewer, if one or more channels have already been
disabled). And this would affect notes coming in over MIDI, but not notes
going out over MIDI.

If it's in the keyboard, a bad electrical connection between the keyboard
and the main board is possible, but that would consistently kill one row or
column in the matrix, which translates into a group of eight consecutive
keys or every eighth key, so that's unlikely.

The most likely possibility, if it's in the keyboard, is dirty key contacts.
My memory is hazy on this, so I could be all wrong about this, but the way I
remember it, it is possible to pop the keys out one at a time, by flexing
the metal tab that the back of the key snaps onto. This will expose the
silicone dome switches, which are in strips of something like eight, and can
be lifted off the board. I think they have little alignment dimples that fit
into holes on the board, to make it easy to put them back correctly. The
board itself has gold flashed concentric contacts under each dome switch,
and the dome switch has carbon loaded contacts, a single center one and a
circular outer one. I don't have any official info on the best cleaning
method, but I've cleaned other similar switches both with alcohol, and with
a pencil eraser on the circuit board.

Again, as I said, that's all a dim memory, but I think that's the way the
keyboard works.

--

Ciao, Paul D. DeRocco
Paul mailto:pderocco@...