Vintage DD turntables. Are we living dangerously?


I have just acquired a 32 year old JVC/Victor TT-101 DD turntable after having its lesser brother, the TT-81 for the last year.
TT-101
This is one of the great DD designs made at a time when the giant Japanese electronics companies like Technics, Denon, JVC/Victor and Pioneer could pour millions of dollars into 'flagship' models to 'enhance' their lower range models which often sold in the millions.
Because of their complexity however.......if they malfunction.....parts are 'unobtanium'....and they often cannot be repaired.
128x128halcro
Hi Lewn,

the problem is that the cold engine has no power ...... the disch turns for a 50-60 seconds then slows down until it stops.
To start it again, you need to help with my hand, keep the 33 laps for a 50-60 seconds and then stop coming back.
The capacitors are ok, the power supplies are ok, the power transistors inside the turntable work ..... all the electronics have been repaired.

I just want to know what electronic component is that marked on the service manual called "3 hole elements" and that it is inside the engine .... i do not want to open the engine unless it is needed.
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Hi lewn,

I have read many old papers and found the problems of your TT-101 written a couple of years ago.

The result of my labors was to make an intermittent problem into a permanent one! Here is the failure mode: The tt comes up to speed based on the tach reading "33.33", but very shortly thereafter, within less than a minute, you will see readings suggesting the speed is off, 33.32 then 33.34, etc, typically. At that point, the motor shudders significantly and shuts itself down; the platter coasts to a stop with no brake action. The tach goes blank, except for the decimal point.
That's the story.

This problem is what happens to my turntable.

Did you find the cause of this, Mr .Thalmann told you what is the problem?
Or better chance you can ask Mr. Thalmann how he repaired your turntable from this defect, what components had to be replaced?

Cheers


Three hall elements = hall effect sensors.  They control the commutation. 

If the display blanks and the motor coasts to a stop, the over-current protection circuit is being tripped.  

This is a picture of the sensors - the windings are on the other side of the board.  This should show enough detail that you can trace the wires connected to the sensors to allow you to test them without opening the motor.  

http://fidelisanalog.com/wp-content/uploads/sites/3/2017/09/IMG_1634.jpg
With all due respect to Mr Thalmann, he did not repair my TT101, perhaps because my TT101 always worked properly when it was at Bill's shop in Virginia. That is to be expected when something is "intermittent".

JP fixed my TT101, and it still is working perfectly to this day.  Do what JP says.