Help! Thorens TD160 Motor rumble and motor azymuth issues!

[TellMeWhy]

While adjusting the motor azymuth I managed to over tighten the adjustment screw mechanism so that it now turns in it's housing and serves no purpose. To get around this I found a simple solution by glueing the motor mounts correctly in place with epoxy. Now everything works fine, but I notice a pulsating bass rumble / hum quite noticeable in lead in / out and between tracks. Have no idea if this rumble was there before, but I expect not.

When the motor is switched on but no belt connected the noise is gone, so I am pretty sure this comes from vibrations transmitted through though the belt.

My question is, have I caused this motor rumble by fixing the motor in place?

And: should I try and fix the motor azymuth screw or fix the motor in place this time with some form of isolation between motor and plinth? Is it wrong for the TD160 MK1 motor to be firmly fixed in place like this or might I have another issue here? Might I be able to source a replacement motor azymuth adjustment bolt from somewhere?

General Observations-
- TD160 MK1 in good condition
- motor shaft is polished and not bent
- new Thakker belt is fitted
- clutch and pully disassembled, checked and rebuilt, works fine
- have tried replacing motor caps + resistor and doubling value for motor run cap
- have tried shaft bearing "anti-knocking" kit
- platter, subplatter and plinth lightly damped with cork (glued in place with silicon)
- motor and bearing shaft oiled with sewing machine oil
- motor runs seemingly quiet with very little mechanical noise / no audible knocking

All help and suggestions greatly appreciated!

Cheers,

Jon

 

[TellMeWhy]

If anyone is interested, or has the same issue, indeed the noise was motor rumble, most likely due to the rigid fixing of the motor mounts. I got around it by applying copious amount of Dynamat on the plinth and motor itself. This has damped the chassis really well, and the motor rumble is no longer audible at normal listening levels.

 

[T68]

Dunno if it can be of help but I cured the rumble on my Garrard Zero 100 by changing to soft motor mount grommets made of silicone. There´s a Swedish fella who manufactures and sells them on the Swedish auction site Tradera (ships internationally). I think has them for some thorens models too. Hope it´s ok to post a link (no afiliation)
https://www.tradera.com/profile/items/421449/to00si