Hi, I recently obtained a Yamaha JA1701A Rotary Speaker assembly that I was told was removed from an organ or rotary speaker cabinet (Possibly a Yamaha RA-50). I repaired the circuit board and it runs on 110V AC supply. I have the two speeds working fine. By joining the red wire and white wire for slow speed and fast speed can be selected by linking the red wire to the yellow wire. Speaker is working fine.
Would anyone know how I could regulate the speed in the fast setting (red and yellow wire joined together) without damaging anything? It would just be a little more versatile even though I like the two speeds.
Thank you.
Would anyone know how I could regulate the speed in the fast setting (red and yellow wire joined together) without damaging anything? It would just be a little more versatile even though I like the two speeds.
Thank you.
The motor appears to be of the synchronous or asynchronous shadow pole type. So you'd need to vary the frequency.
Best regards!
Best regards!
I carried out the speed control modification to my Yamaha JA1701A rotary speaker utilising the details from the RA-50 service manual. I fitted the 5K linear potentiometer and 2.7K resistor into the fast speed wiring exactly as shown in the manual. It works perfectly. So can now switch between a fixed slow speed and a variable fast speed. Thanks to all for their advice and info. Appreciated.
I'm quite astonished as the schematics at the SM's page 4 shows that the motor speed is controlled by the motor current, not by the frequency. As it's an asynchronous motor with a phase shift helper winding, I dunno how that works 🙄.
Anyway, congrats to your successful modification!
Best regards!
Anyway, congrats to your successful modification!
Best regards!
I have one of these and appreciate knowing that the mod works. Interesting about the motor design. Yamaha has been a pretty amazing company.
Rockies914, I am happy to send you the details of the mod I carried out, if it will help you.
Thanks! 🙂 I have a RA100 service manual that shows a 5k potentiometer, in line with a 2.7k resistor. Is it that easy?
I'm looking to do a remote control at some point . I should be able to run a few wires for (say) 20 feet for starters, then rig up something like an Arduino with a relay, and (eg) digipot depending upon the current/voltage requirements of the circuit 🙂
Sounds like a plan. I had considered running a cable out to a home made foot controller but decided to keep it all local to the cab. Keep me posted on your progress. I will be interested in what you do.
I will for sure. It should be easy, just a networkable, rudimentary SBC with a breadboard "cape" (my Beaglebone Black is overkill though, haha!).
If you happen to have the RA50 service manual in digital format, my version of the RA100 isn't the greatest 🙂
If you happen to have the RA50 service manual in digital format, my version of the RA100 isn't the greatest 🙂
Thanks very much! Much better than what I had. It looks like the voltage is less than 6v so that makes things easier. I'll put a digipot on my next parts order and see if I can whip something up 🙂 It will be awhile but I'll post back with the results for certain.
I need to figure out how to remotely control the speed of a Leslie horn (using a variable speed motor instead of the 120vac relay switching) as well, and hopefully I can use the same SBC.
I need to figure out how to remotely control the speed of a Leslie horn (using a variable speed motor instead of the 120vac relay switching) as well, and hopefully I can use the same SBC.
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