Fixing up a warbly Roland D-5

[charla]

I’m attempting to restore a Roland D5 found in an op shop (thrift store). It looks in great condition, internally is clean, keys respond nicely.

My problem is that there’s a distorted warble/underwater sound to the notes when played in performance and multi-timbral modes. The ROM play demos play beautifully, as do the manual drums. Occasionally I’ll get a brief ‘check internal battery’ message, despite a brand new battery.

Troubleshooting so far: Ran the test mode – all good except for a flutter in the pitch bend (it registers -127, 000 and +127, but the number on the right flutters).

Disconnected the bender wheel from the main board, but still get the distorted sounds.

I’m wondering what my next steps should be. I had read that a capacitor between brown (AGND) and yellow (Vref) on the bender pot fixed this problem for others, but does the fact that I disconnected the bender and still had the same problem indicate that this wouldn’t work? Should I test/replace capacitors on the board? If so, which capacitors should I test, and what reading would indicate that it’s failed?

C49 and C35 look like maybe they have some kind of ‘sprinkle’ around them… but maybe I’m clutching at straws. Can post photos and audio of the distortion if you think it would help.

These links have been helpful so far: https://electro-music.com/forum/topic-45858.html

http://www.synfo.nl/servicemanuals/Roland/D-5_SERVICE_NOTES.pdf

Disclaimer – I am a very novice fixer of electronics. I do it because I like trying things and fiddling and when it works, it’s so rewarding. But I’m still very much learning, so please dumb it down for me!

Thanks in advance for all your help. Looking forward to making some sounds with this baby – the demos are awesome. Happy to provide any more info.

[charla]

For anyone coming across this in the future - I took a punt and replaced capacitor C49 - the synth plays like new. I had read about doing this within the pitch bend pot but once I got it open that looked way too fiddly for me, so I just replaced the cap on the circuit board. Used a 10uF 25V 105°C electrolytic cap (rather than a 16V) on the advice of a nice person on Reddit. Relatively easy fix.