Kawai E550 Expression Pedal information needed

[Scott from Oz]

Hi all,
A friend of mine has a Kawai E550 organ that has a problem with the expression pedal. The volume increase is not smooth when depressing the pedal. Does the E550 use a volume pot for expression or is it an LDR system? If LDR, what would cause the volume swell to be uneven?
Thx
scott

[geoelectro]

Looks like it uses a 10K pot for expression. If you want a quick fix try this. Pots have contacts inside that get "dirty". They can actually be cleaned IF you can get some cleaner inside. Some pots have openings where the three terminals go in. More quality pots are sealed to prevent dust etc. from entering. That is the kind most often found. If you look at the construction of a pot you can see that the back is actually a cap covering the internals. By carefully prying the cap away from the body, you can get it open enough to get some spray cleaner inside. Then reseat the cap. Another way is to drill a small hole into the cap so you can get some spray inside. I use a magnetized drill bit which will help keep too many filings falling inside. DeOxit D-5 works well working the pedal back and forth after application.

Otherwise, finding a replacement is the best. I don't know if it a linear or log pot. The schematic says 10KE and it controls a transistor that actually controls the volume so I suspect linear. It goes from the transistor to ground.

Good luck!

Geo

[Scott from Oz]

Thanks Geo, much appreciated
i wanted to clarify what I was dealing with before pulling the thing apart.
cheers
scott

[andyg]

It's done well and lasted 40 years! Just before the E550 came out, we had a run of organs with poor swell pedal pots, the E500 seemed to be prone to that. But I've never come across it on an E550 until now. Given its age, we'll forgive it! :)