Any techs for hire in SoCal to fx a hum in a Yamaha Electone FX-20?

[JeffW]

Much thanks to fredy2 for remote diagnosis on the hum in my Yamaha Electone FX-20.

My initial email to fredy2:

I haven't found mention on the OrganForum of a problem I sometimes, but not always, have with my Yamaha Electone FX-20.

When I first got it, after turning it on there would be no sound until the speaker relays clicked. Once I heard that click, a pitched hum started and it was a little higher (sharper) than B flat below middle C. That hum continued as long as I had the organ on. Increasing and decreasing the volume pedal OR the master volume control didn't change the volume of the hum.

About a month after I got it, that hum disappeared for 10 months. But it started up again 2 months ago.

His well-experienced reply:

That would be about 240hz... or fourth harmonic of the 60 hz power frequency. You may actually be hearing 120 hz which is second harmonic of the power frequency. This would be indicative of failing filter capacitors which may happen at the age of these organs. Analysis with an oscilloscope is best approach...find a friendly tech to help. The fact that sound happens only when the speaker relays close means the amps are driving the signal... if the scope shows frequency is really 120 hz then scope the power supplies to find the one with excessive ripple and replace the filter caps.

Any techs for hire in Southern California that could come by to check-up/touch-up a Yamaha Electone FX-20?

[andyg]

Google mitatechs and you should find listings of service people in your area. But do be aware that some of them will choose not to work on older instruments and that many owners of oldies do their own maintenance.

If you're paying a tech to do this, then consider asking him/her to change all the caps in the power supply in one go. If one or two have gone bad, there's a chance that the others might. So you can future proof the repair.

[JeffW]

Thanks for the pointer andyg!

I spoke with a service person this afternoon and we're coordinating to schedule a look at the FX-20--I found him through the www.mitatechs.org website and he's only about 13 miles away.

Cheers!