Vibration on TD 125 reaching the tonearm

[varunbadola1974]

Gentlemen,
I have hit the wall in the last phase of my TT repairs. I have put a new motor on my Thorens TD125 and changed it from an AB to LB. The problem that I am facing is that with the belt on, the vibrations of the motor reach the tonearm. Without the belt the motor runs quiet. If I push the left back side of the suspended sub chassis, the vibration does go down considerably. If I put my sub woofer on, I can feel the vibration being passed on to the sub too. I faced this problem with my previous motor too, before it gave up on me. By the look of it, it does not look like an electrical problem. But I have not been able to solve it. Any input would be welcome. Thanking you.
Varun Badola

 

[G401fan]

Is the motor suspended on some sort of rubber bushings or grommets? If those are worn out due to age, then the pressure exerted by the belt (when the motor is turned on) could be dragging the motor slightly, but enough to make it, or its hanging metal elements, come in contact with the chassis, hence the noise and vibration.

 

[arj]

Can you post a picture of the setup showing the motor and belt. Just guessing but it could be that when the belt is connected, the motor vibrates ?

 

[varunbadola1974]

Sir no matter what I try, my files are always too large to be attached. I have started feeling the vibrations on the body too now. Nothing seems to be connecting the two chassis. The vibrations are only felt with the belt on.

 

[varunbadola1974]

Is the motor suspended on some sort of rubber bushings or grommets? If those are worn out due to age, then the pressure exerted by the belt (when the motor is turned on) could be dragging the motor slightly, but enough to make it, or its hanging metal elements, come in contact with the chassis, hence the noise and vibration.

Yes sir. Only with the belt on, the motor vibrates

 

[varunbadola1974]

Can you post a picture of the setup showing the motor and belt. Just guessing but it could be that when the belt is connected, the motor vibrates ?

Yes sir. Only with the belt on the motor vibrates

 

[varunbadola1974]

Yes sir. Only with the belt on, the motor vibrates

The motor does not use any rubber gourmets. It is planted straight on to the sub chassis.

 

[arj]

Yes sir. Only with the belt on, the motor vibrates

have you seen this thread ?

Thorens td 125 motor vibrates back and forth- Vinyl Engine

www.vinylengine.com

 

[rikhav]

Sir no matter what I try, my files are always too large to be attached. I have started feeling the vibrations on the body too now. Nothing seems to be connecting the two chassis. The vibrations are only felt with the belt on.

Try the photo resizer app. Decrease the quality or the size and then it should get attached

Alternatively send photos to a friend or anyone at home on WhatsApp and tell them to send you back same photos

Attach to the site the pictures you got back


Hope you resolve your TT motor issue soon

 

[varunbadola1974]

have you seen this thread ?

Thorens td 125 motor vibrates back and forth- Vinyl Engine

www.vinylengine.com

Yes I have. My motor is brand new and the PCB has new caps.

 

[varunbadola1974]

Gentlemen,
What are the chances of a motor vibrating due to loose connections to the PCB?

 

[arj]

if its a dc motor then maybe there is an effect due to the PCB . Better rule out mechanical issues first Since this happens only when you put the belt ie with the load.

I do not know much about the TD125 but If i were to guess
1. is the belt placed correctly on the motor ?

2. Is the motor spindle is loose/wobbly by any chance ?

3. what is curious is the the vibration going down when you press the suspension ..could it be some resonance being reached ..maybe retuning the suspension will help.

again..not very sure since i dont know much about this.

 

[TD150]

Cause of vibration can be:-
1). Motor mounting not isolated.
2). Motor spindle has play. Etc
3). Belt too tight and titling the motor angle
4). Main spindle bearing lubrication
5). Main spindle bearing ball corrosion/ defective.

You may check the individual points above and identify whether the vibration is caused by motor or the main spindle bearing. Sometimes dry main spindle bearing can cause friction and vibration.

 

[varunbadola1974]

All the above points checked TD150 sir. I opened up the TT and refitted the motor. Now the motor starts with a shudder, vibrates and then settles down. It is a NOS motor. Could that be the reason? I know that these motors are suppose to run dry. But would a drop of oil help here.

 

[TD150]

You may try a drop of oil at the motor shaft. Check also the voltage arrived at the motor, though that should not be any reason for vibration, but to keep the motor safe. Actually the motor should start smooth and silently.

Try to touch or put pressure by holding the motor shaft while it is on and check if it vibrates.

How about the main spindle bearing oil well. Is it properly lubricated? Is there any residue or impurities which may cause hurdle in smooth rotation.

Remove the rubber belt and rotate the platter and check if there is any vibration. Without the belt fixed switch on the motor and check if it vibrates. Further in the said position (without belt motor on position) rotate the platter with hand and see it it vibrates. You may get a clue where vibration comes from.

Ideally the vibration is from mechanical and not electronic.

 

[varunbadola1974]

There is no vibration in any other case. I've had this habit of rotating the platter by hand and the switching the motor on. I do it with my belt drives to take away the initial load off the motor. The shaft and the well have been cleaned and are well lubricated too. As I write to you, the motor is settling down on it's own a bit. The shudder in the biggening and during speed change are the only concerns now.

 

[TD150]

Check PM varunbasola1974