1928 Victor Induction Disc Motor & 1931 Dajos Bela Tango Blues - O Sole Mio Berlin Victrola

Servicing a Victor AC Induction Disc Motor, with a Tango Blues by the Dajos Bela Kuenstlerorchester, the leading Band of Weimar Berlin - O Sole Mio (1931), on those fabulous, super quiet Odeon pressings.

Ok, as I said before, after 80 years, the gears deserve to be taken apart, all gears and bushings thoroughly cleaned with aggressive solvent (my choice: MEK), so that the motor can run quietly for another 100 years.

The Victor Induction Disc Motor was one of the great Gramophone motors: Based on Nicola Tesla's groundbreaking patent, this A/C Motor has no brushes or any electric contacts, just to pair of coils and a copper disc rotor. It has significantly more torque than a spring wound motor, and the absence of gears except for the govenor results in even speed with absence of all wow and flutter.

This motor is basically service free, and you just plug it in, and it runs.

Couple of notes and details:

This is the new 1928 version of the motor, the 1925 - 27 version has a different casting which leaves one quarter of the disc exposed, otherwise, servicing them is pretty much the same.

However, the 1928 motor is basically noiseless, whereas the earlier motor tends to hum a little.

- clean out the central lower bushing to remove grit and dirt.
- DON"T FORGET the bearing ball at the bottom of the spindle.
- The gear and the disc fit in shallow holes in the spindle, their position is fixed.
- This motor has two adjustment screws on the disc, which is unusual. Earlier motors have only one. The disc must turn freely without touching anything. If the elevation of the disc in earlier machines needs to be changed, look at the bottom of the casting: A screw and locknut are the bottom of the central bushing, by turning the screw, you can change the height of the bushing bottom.
- You see me screwing up the handling of the disc: The disc is very soft copper. If you bend it, you can throw it away, because the motor only works when the disc is absolutely flat. NEVER PUT ANY PRESSURE ON THE DISC.
- The govenor needs to be cleaned and lubricated. make sure all the screws are tight. The bushing with the groove goes into the central position, the one without groove in the outer. Mount the govenor so that there is a very small amout of play.
- Mount the coils and make sure that the disc does not touch anything.
- Now is the time to fire up the motor. As you see I am adjusting the position of the outer gov bushing to find the quietest spot. Also, the central gear can be slid up or down ever so slightly. This way you will find the quietest position of the gears.
- What I did not do was balance the govenor. If you watch at the blurring govenor in motion, and the weights are pulsing or obviously at different distances, you may need to balance the govenor: In situ, loosen the six tiny screws that hold the gov springs to the gov shaft a turn or two, so that the springs can slide. Power motor up and let it run 5 minutes. Then tighten all screws. If this does not help, you may need to replace all three gov springs, which can be had any number of places for cheap.
- Pre 1928 motors may have some hum. Couple of things to try: the mounting screws must be tight, but play around by loosening them, to see if the hum gets less. Consider putting thin rubber pads between coils and body. Ultimately the hum is caused by coils which are somewhat loose on their iron corese. Victor recommends taking the coils our and weedging thin pieces of wood between core and coil. What may also help is simply putting strips of felt under the motorboard of the turntable, and putting rubber under the motor mounting screws.
- one last word: My preferred lubrication is black Moly-Graphite grease for the gears, and motor oil for the bushings and govenor. I usually take an oil with some silicone additive.

Category:

Music

Tags:

• Disc
• Motor
• Bela
• Movie

[chilldude2007]

There is a bottle of slick 50 in the background. Are you using that for lube?

[sanfranphono]

Yep, I guess even if the oil goes away, the silicone will continue lubing. No idea if this is working. Do you have an opinion?

[sanfranphono]

Yeah I hope, provided that the stuff does not gum up.

I had bad experience with drying greases and evaporating oils, so I use slick for oil and black graphite-moly for grease on the assumption that even when the stuff evaporates, there are still enough solid lubricants left. Let me know what you think.

[VictrolaCredenza]

Thanks for interesting clip. My Credenza rotates stable enough but it sometimes rumbles. Perhaps former owner attempted to flatten the rotator???

[sanfranphono]

Don't know exactly what you mean by rumble, but that sounds like something from the govenor, or most likely the gears.

If you watch the disc from its edge, you see if it is not running quite true.

What I would do is take out the gov and the gears, incl bushings, clean everything, and the slightly play around with the position of gov and gear to find the quietest meshing point for the two (you see me do that at the end starting at 3:35.)

[spannerworks1]

Excellent video and very educational. I find the comments very helpful.

Regards

Richard

[sanfranphono]

Yeah, if you have ever tried to straighten out a bent disc, you will know the problems. Even if you get it straight so that it doesn't touch any more, the motor will have a swelling hum with each rotation.

Cheers, more to come ...

[chilldude2007]

I think it's a brilliant idea. Probably 10 times better than regular oil. I'm going to try some myself !