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Gates broadcast turntable problems

Chriswashere

Chriswashere

Active Member
Hello, I'm trying to repair a Gates broadcast turntable for a friend, and I just can't figure it out. The table runs at the right speed a few minutes after power-up, but as time goes on the table gets slower and slower.

It has a new idler, so what else could be the issue? I believe it is a cb-77 or something.
 
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KentTeffeteller said:
Has the motor been serviced properly? Are the motor mounts in good order? I am near Knoxville, and might be able to assist you if need be.
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The motor has not been serviced according to what the owner said. I tried myself, but the motor won't come apart. Usually servicing the motor is my first step, but this one is a pain. The motor mounts seem to be ini decent condition as well. I would certainly appreciate assistance if it comes to that, but hopefully the problem can be solved.

On this motor there are 2 little spouts, one top, and one bottom. Are these for oil possibly? I'm used to dealing with Dual tables, so this is a bit new.
 
Everything is greased and oiled as it should, which is what's baffling me.

While playing, the table actually just stopped, but the motor kept going. It's getting more and more strange.
 
I believe this unit has a 2uF motor capacitor, the failure of which will cause the motor to generate insufficient torque. I'm sure somebody will put me right if I am wrong!
 
I just replaced this cap with no improvement. There is a 200 ohm resistor that reads as "214" ohms, but I doubt that's the problem.
 
There's not a lot on the web for this TT. From what I can see the drive looks complex. Some photos would help. Most idlers are set up so the idler wheel gently wedges itself between the platter and the capstan when something attempts to slow the platter down, such as a fully automatic table, which this is not. So it may rely on spring tension alone.
 
Transmission could be an issue, but the table starts out at the correct speed which is why I'm so lost with this repair.

Also, the motor gets extremely hot in a short period of time, hot enough to burn yourself.
 

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It sure sounds like it is going into a bind. A shaft that turns, motor /spindle. I would take it apart. Look for hot spots. Put any shaft between centers and check for run out.
 
It sounds like you have two issues. A hot motor that turns and a platter that slows to zero while the motor is working. Adding oil to a dirty motor is like putting water on wax paper. That is why you're overheating - and the tension on the puck against the platter is off - IF - you have observed the motor running continuously while the platter is off.
 
The motor is a synchronous running one at 600rpm can you check the rpm after cold start and when its hot wothout driving the idler ?
 
Chriswashere said:
I just replaced this cap with no improvement. There is a 200 ohm resistor that reads as "214" ohms, but I doubt that's the problem.
Click to expand...

The cap that you changed, and the resistor, may just be a snubber network across the switch - a suppressor, effectively. Therefore not the capacitor in question. I'm not overly familiar with these units, so I'm willing to stand corrected. However, you state that the platter slows down whilst the motor continues to run, but how can you see that the motor's running with the platter on? Are you looking at it from underneath the chassis?
 
I suspect that motor is going to need attention and so will the idler wheel's actuation system. That motor is begging to be torn down and cleaned and relubricated properly and worn bearings or parts replaced. And reassembled properly.
 
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