Post by Chipfree on Nov 5, 2020 17:22:07 GMT
Hi - I’m working on a Rockola Rocket model 1434. My issue is this - the turntable motor is quite sluggish and often doesn’t have enough torque to start up the turntable platter. When it does run it is consistently slow. Here is what I have done to date:
1. Aligned the turntable shaft bushing with the upper turntable bushing and ensured upper bushing rotates freely and is lightly lubricated with 10W non detergent oil.
2. Cleaned and lubricated the flywheel hub inside for the turntable shaft and outside for the flywheel.
3. Replaced idler wheel, cleaned and lubricated the shaft it rides on.
4. Cleaned and lubricated upper and lower bushings on the turntable motor, turns freely with no binding.
5. Checked the microswitch supplying power to both the upper and lower sets of windings and removed the capacitor across the microswitch contacts.
This particular design of jukebox requires a lot of torque to overcome the mass it has to turn, ie the motor shaft turns the idler wheel which then turns the flywheel. As the turntable shaft rises it engages the flywheel via the clutch spring. It then grabs the record, the top of the shaft hits the upper turntable bushing assembly and finally the tonearm needle hits the record. It seems like a lot of load but I like to assume that it worked correctly from the factory so what has changed or degraded over time? The only noticeable damage I can see is a few of the vanes of the small fan on the bottom of the motor are missing. The manual describes the motor (Rockola part no. 15182) as a “Russell Tandem Turntable Motor No. 239 Model 23320 78 RPM constant speed 110 Volts 60 cycles”. The top winding runs the flywheel clockwise, the lower winding runs the flywheel counterclockwise.
My questions are as follows:
1. Other than mechanical friction that I hope I addressed by doing the above, do these AC turntable motors degrade electrically resulting in a loss of power?
2. Is it possible or even practical to rewind these motors?
3. Could the missing fan blades cause an imbalance slowing the motor down?
4. Any other suggestions as to what else I could try to improve the situation would be welcome.
1. Aligned the turntable shaft bushing with the upper turntable bushing and ensured upper bushing rotates freely and is lightly lubricated with 10W non detergent oil.
2. Cleaned and lubricated the flywheel hub inside for the turntable shaft and outside for the flywheel.
3. Replaced idler wheel, cleaned and lubricated the shaft it rides on.
4. Cleaned and lubricated upper and lower bushings on the turntable motor, turns freely with no binding.
5. Checked the microswitch supplying power to both the upper and lower sets of windings and removed the capacitor across the microswitch contacts.
This particular design of jukebox requires a lot of torque to overcome the mass it has to turn, ie the motor shaft turns the idler wheel which then turns the flywheel. As the turntable shaft rises it engages the flywheel via the clutch spring. It then grabs the record, the top of the shaft hits the upper turntable bushing assembly and finally the tonearm needle hits the record. It seems like a lot of load but I like to assume that it worked correctly from the factory so what has changed or degraded over time? The only noticeable damage I can see is a few of the vanes of the small fan on the bottom of the motor are missing. The manual describes the motor (Rockola part no. 15182) as a “Russell Tandem Turntable Motor No. 239 Model 23320 78 RPM constant speed 110 Volts 60 cycles”. The top winding runs the flywheel clockwise, the lower winding runs the flywheel counterclockwise.
My questions are as follows:
1. Other than mechanical friction that I hope I addressed by doing the above, do these AC turntable motors degrade electrically resulting in a loss of power?
2. Is it possible or even practical to rewind these motors?
3. Could the missing fan blades cause an imbalance slowing the motor down?
4. Any other suggestions as to what else I could try to improve the situation would be welcome.
