Noisy Induction Motor on Orthophonic Victrola

[nmonty93]

Hi everyone,

 

I am new to APS (USA membership) - glad to be here! This is my first post on the forum.

 

I am also new to electric, motor-driven phonographs (but not the acoustic, spring-driven variety). Earlier this year I acquired a VE7-25X. This particular model has the induction disc motor to run the turntable. There lies my issue (I searched this forum for previous threads with no luck).

 

I have found that the motor can go from running at a "barely audible" hum (good) to a very loud hum (unbearable). Even closing the lid while playing records cannot drown out the loud hum.

 

I can't seem to find any patterns. Sometimes I can play 10 records in a row without issue. Other times I can play 2-3 and the loud hum/buzz will occur. And even other times the motor hums when playing my first record of the day. That being said, I don't think the motor heating up is the root cause here.

 

I have checked the motor's components and cannot find any signs of looseness. I will go back and double-check though as that could be easy to miss. I also checked my switch for any potential root cause to no avail. I even thought the auto-brake could be sending some force to the motor causing the hum. I haven't tried to "soft/manually brake" my records yet to see if the loud hum still presents itself - an experiment for another day.

 

Any thoughts on how to eliminate this issue? As stated before, the loud hum/buzz will come and go without any apparent pattern. Sometimes it can sit for a day and go away, other times the buzz is still present. Perhaps the motor just has to be rebuilt, but I've heard many say it's better to leave these untouched if they are still "running".  Oh and one more note: I did grease/oil the motor's various components when servicing the phonograph a few months ago.

 

Thank you in advance!

Nate

[rbarnett]

Here's a picture where I've placed bamboo shims on my coils.  Bamboo is harder than most woods, and the shims need to be tapped in firmly with a small hammer. Experiment with placement, and you should be able to reduce the hum.

Bob

Bob

Edited October 16, 2021 by rbarnett

[nmonty93]

On 10/15/2021 at 2:55 PM, Auxetophone said:

I don’t have one handy to photograph, but you’ll need to place paper shims between the coils and frame to stop that hum. It’s a very common problem on induction phonograph motors. Perhaps someone else can chime in with a photo or diagram for proper placement. 

Wonderful. Thank you! I will give this a try this weekend. Appreciate your help. 

[nmonty93]

On 10/16/2021 at 2:08 PM, rbarnett said:

Here's a picture where I've placed bamboo shims on my coils.  Bamboo is harder than most woods, and the shims need to be tapped in firmly with a small hammer. Experiment with placement, and you should be able to reduce the hum.

Bob

Bob

Thank you for the photo! This really helps. I'll give it a try this weekend. Not sure where to get the bamboo shims! I'll see if I can find some online. They actually appear to be bamboo needles you have there? I have some on hand. 

Edited October 19, 2021 by nmonty93

[electrolaman]

If you are going to use bamboo needled be sure to put the pointed long edge of the triangle against the metal and not the coil. That could cause a break in the coil wire. It is really best to make up some flat wedges to use. 

 

 Carlton Smith

 Indianapolis, In

[rbarnett]

1 hour ago, electrolaman said:

If you are going to use bamboo needled be sure to put the pointed long edge of the triangle against the metal and not the coil. That could cause a break in the coil wire. It is really best to make up some flat wedges to use. 

 

 Carlton Smith

 Indianapolis, In

You're right, Carlton! I have bamboo wedges left over from making needles and should use those as you suggest. Time to go in and make the fix!

Bob B