Roland D-50 D50 keyboard repair forum..

[vern]

Hi. I'm new at the computer and don't even know if I'm doing this right, but the Key Transpose, Chase, and Portamento buttons on my D-50 don't work and one of the keys sounds louder than all the others and if I could get help with these problems and/or get one of these D-50 service manuals I would greatly appreciate it. Any advice on how to download it and print it would also be welcome. I have Windows XP if that helps.

[Enzo]

Hey Vern.

If those are push buttons on the panel, then a good possibility is that the tiny push switchs under the panel button needs replacing. Usually they are common types, available at places like Mouser.

I don;t know which format the key switches are in, probably rubber contact strips. There will be two contacts under each key. When you press a key, it closes them. One slightly after the other. The computer in the machine uses the amount of time between the two closures to calculate how fast you pressed down the key. We call that velocity sensing. If the second contact is stuck closed, then the instant the first one closes, the computer senses the second, and assumes the maximum velocity. Thus maximum loudness for that note.

SOmetimes just removing the rubber contacts, cleaning them and the board they are on, and reassembling will cure things. But look close at the rubber for that key and see if it is damaged in any way there.

If the key contacts are metal blades, see if the normally open blade is bent up towards the moving blade.

[doctor]

Hey Vern.

If those are push buttons on the panel, then a good possibility is that the tiny push switchs under the panel button needs replacing. Usually they are common types, available at places like Mouser.

I don;t know which format the key switches are in, probably rubber contact strips. There will be two contacts under each key. When you press a key, it closes them. One slightly after the other. The computer in the machine uses the amount of time between the two closures to calculate how fast you pressed down the key. We call that velocity sensing. If the second contact is stuck closed, then the instant the first one closes, the computer senses the second, and assumes the maximum velocity. Thus maximum loudness for that note.

SOmetimes just removing the rubber contacts, cleaning them and the board they are on, and reassembling will cure things. But look close at the rubber for that key and see if it is damaged in any way there.

If the key contacts are metal blades, see if the normally open blade is bent up towards the moving blade.

Hi Vern,

The D-50 is not easiest device for repair. You should think twice
before you start doing something.

But if nevertheless you want to try, here are the recommendations:

Keyboard contacts problem.

D-50 uses rubber contacts (Roland p/n 22185218) that are obsolete
long time ago. The only possible procedure is contact cleaning.

There is detailed description how to clean D-50 keyboard:
(D-50 | Key Contact Repair ).
See attentively and think again whether makes sense for you to do it.

Switches problem

D-50 uses SKHHAMA010 tact switches (see attached datasheets)
manufactured by ALPS (Roland p/n 13169633).

For this vertical type switches footprint (holes placement) is 6.5mm x 4.5mm
and stem height H = 5mm.

You can replace it with any switch having identical footprint and stem height
(operation force is less critical).
Possible replacements are Digi-Key p/n P12192S-ND or Farnell p/n 1555982.

Take into account additional circumstance: if you have disassembled D-50
and boards with switches are in your hands, check all switches (not only
those about which you know that are out of order) by means of ohmmeter.
Resistance of closed (pressed down) switch should be less then 10 Ohm.
You will be surprised how many switches are going to die.

Replace all of them!

Good luck.

[Enzo]

Those are the switches I had in mind. I buy them 30-40 at a time, and they are cheap. Just make sure to get the right height ones. If you put the 4.5mm ones in where 5mm ones belong, the p[lastic panel button won't quite push them down. Of if you get them too tall, the plastic button will push them down just sitting there. Once I have gone to the trouble of pulling the panel circuit board to get at teh switches, I find it is simpler to just replace all fo them at once rather than trying to figure which ones are worse off than others.

If your rubber contact strip is torn, if nothing else, it might help to move the bad strip to the top or bottom octave and use the good one froom there in its place. Usually the damaged ones are in the center octaves because they are the most played.