Yamaha Electone TX-1

[sread]

I just bought a Electone FX-3 with 2 TX-1 Tone Cabinets. Everything works except one of the Tone Cabinets. It powers on, but no sound. I have looked all over the web and cannot find a Service Manual anywhere. Any suggestions for what to look at and where I might find a Service Manual?
Cheers and Thanks...

[joecool240]

See attached.
Joe

TX1.pdf

[joecool240]

I have repaired several TX-1's that were either dead or a channel that was distorted. In all cases it was one or more of the STK amplifier modules that failed and caused the speaker protection circuitry relay to disable the speakers.

Joe

[sread]

Thanks Joe! Since I am a novice electrician, is this something I can fix by replacing a resistor or cap? Or, do I need to take it to an amp tech?

[joecool240]

This amp is not easy to work on. It only takes any one of the four STK amp modules to fail (shorts DC to the output) to trip the speaker protection relay.
A couple years ago I repaired two TX-1'S connected to a Yamaha FX-1. Among the two cabinets were three dead channels and one distorted, tripping the protection relays and disabling the entire speaker. I replaced 4 of the STK amp modules and all was well. The trick was to go in the amp and make measurements to see which STK's were bad.

You can still get these STK's, but they are a challenge to replace in the TX-1's.

Joe

[sread]

Joe, Where do you get the STK's? Is there a site that sells NOS?

[joecool240]

Each cabinet has three STK-085 amp modules, and one STK-089 amp module.
I got mine on eBay about two years ago. There are some listed on eBay right now:

https://www.--------/itm/STK085-Orig...4AAOSwlsFa311D

https://www.--------/itm/STK089-Orig...kAAOSwDN1UNtbD

[sread]

Thanks! I just bought one and made an offer on the other.

[joecool240]

Keep in mind, the problem "could" be something else, not the STK's. It's just been in my experience with TX-1's, the problem was STK amp modules.

[sread]

Understood. In your previous post you said "The trick was to go in the amp and make measurements to see which STK's were bad". What measurement were you looking for when you tested the STK module?

[geoelectro]

Measure the output pin (7) for any DC voltage. It should read zero if operating correctly.

Geo

[sread]

Got it. Thanks I plan to get to it this weekend.
BTW - I was able to find the Service Manual - hard to find. It's too big to upload. Let me know if anyone wants it and I can put it up on a share.

[gmcfry]

I would love to get a copy of that service manual. I just got a Yamaha FX-3 with one TX1. When I power them on, the red light glows on both the organ and the speaker, but I'm not able to get the organ to do anything. No sound, and when I press any of the feature buttons, no lights come on. I'm hoping it's just a blown fuse or something simple, but I know it's probably not. Any advice?

I'm also looking for an Owners Manual for the FX-3. Any ideas???

Thanks in advance!
Gerald

[gmcfry]

Problem solved!