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Thorens TD124 Motor Dead

B

Bob Stewart

New Member
Wondering how to test coils in a Thorens TD124 E50 motor. Plug it in and nothing happens. Motor spins free but wont power up. New machine to me so Know nothing about the past. Any help would be greatly appreciated.
Bob
 
Are you getting anything, e.g. is the strobe light on? I’d check all connections below and make sure no leads have come loose from anywhere, also check the switch continuity (obviously disconnected from mains!). I’m assuming the voltage selector pin (under the platter) is present and correctly installed? If that is missing I’d guess it won’t run.

Also expect the spark suppression cap to have failed, though that shouldn’t stop it running (it can stop the deck powering off if it shorts!). I’m not sure how to check the coils though as I’ve never had to do that. AudioSilente (eBay) sell replacements, so all is not lost if they are shot.
 
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It has been some decades since I've smelt the backside of TD-124, but doesn't the voltage commutator have a power dropper resistor present?
 
That is a nice wiring diagram by user510 over there. The resistor appears to be 33k, worth having a look, as it may have gone OC.

Here is a handy demonstration video of how to test motor windings using a multimeter...


P.S. With your standard Philips/Airpax/Premotec type AC synchronous motors, it makes sense to common the two black or grey return wires during test, such that one doesn't get a false OL reading by connecting across the +ve of one coil and the -ve of the other.
 
The 33k wire wound resistor only feeds the neon strobe lamp and nothing else.
Is the voltage selector screw fitted and tight? If so, you will need to remove the voltage selector screw, remove the bottom cover over the motor winding/voltage selector terminals check that none of the wires have broken off. If OK check continuity of the coils, using a DMM, on each set of motor winding cables, ie red>black =82R, black>yellow = 26R, yellow>green = 91R. The readings should be very close to these within 1-2R. If any one is open circuit or low resistance I suggest the motor needs new set of coils. Audio Silente is Italy is a good place to start.

John
 
I’ve had something similar before on a 124. Turned out that the felt bushes that support the bearings had dried to such an extent that it allowed the armature just stick to the coils when power was applied. You could feel the pulley vibrating but it would not rotate. To all intents and purposes it looked dead. New felt bushes and bearings and it was fine. They are pretty rugged motors. Of course you could have a wire off, further investigation required, just don’t forget it’s 240v
 
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