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Roland D-5 Keyboard scanning problem, need help.

Posted: Wed Oct 21, 2020 1:38 pm
by stevefuzz72

I have a Roland D-5 that came to me with all sort of problems.
After a full cap job and tact switches replacement, everything works fine now, with the exception of a keyboard issue.

Here's the problem.
Both in "Performance Mode" and "Multi Timbral Mode" when I play single notes everything is fine, but if I keep the lowest F1 depressed and then play C#2 - A2 - F3 - C#4 - A4 -F5, one at time, no sound is produced.

I've run all the keyboard internal tests which gave perfect results.

You cand download the service manual from here:

I've made a video showing the problem:

Re: Roland D-5 Keyboard scanning problem, need help.

Posted: Mon Oct 26, 2020 7:25 am
by Rasputin
Just on a hunch, I would check all the diodes in the keybed, particularly the ones pertaining to your semi-non-working keys.

Re: Roland D-5 Keyboard scanning problem, need help.

Posted: Tue Oct 27, 2020 1:45 pm
by madtheory
Rasputin is right. I think first thing would be to check that diodes (and any resistors) and the board is OK at that F1 key.

After that, this kind of fault can be caused by the keyboard not being seated back in to the unit properly, causing a (temporary) short or breaking a cable. A part of the board might get moved when you press that F1, so you'll have to see if you can observe that in action.

There's probably a circuit diagram for the keyboard matrix. You'll see there which keys share lines. You probably have a short or a broken connection on one of those lines. With the circuit diagram you can trace where the damage might be.