Rock-Ola 1494 sound Quivers or Wobbles a little

[gordo]

Hi All,

I have a Rock-Ola 1494 that I have rebuilt. This jukebox has had a hard life.

The jukebox now plays well, however, on long notes (in some records) the sound tends to 'quiver' or 'wobble' a little.
It sounds like a slight slippage of the record or turntable.
I have replaced the rubber drive wheel and tension spring.
Also the felt on top of the turntable has been replaced and the turntable thoroughly cleaned and dried.

As I am in Australia, we have 240 volt, 50Hz power.
A stepdown transformer solves the 110/240 volt issue.
Because of the 50Hz power a 'spring', is attached over the top end of the motor shaft to increase it's size from 3mm to 5.1mm.
This alters the motor speed to make adjustment from the 60Hz power to 50Hz power.
The records now run at 45 rpm.
I checked the speed and it is consistent over 1 minute.

I have lubed all the parts and checked tonearm weight.

Any idea what may be causing the sound to 'quiver'?

Any help greatly appreciated.
Kind Regards
Gordon...

[Ron Rich]

Hi Gordon,
Did you replace the tension spring with exactly the same (correct) type ? That spring is critical, in the performance of that system ! What type/weight was the oil you used ? Did you oil the motor--both bearings, and if so, with what ? How are the motor grommets? are the "supports" (if used) still in place ? Is the mechanism suspension, free to "float" ?? What is the needle pressure set at ?? Any one, or combination of the above can cause this problem ! Ron Rich

[gordo]

Thanks Ron,

I will work through these one at a time.
I did not use the exact spring, I used a similar size that I had lying around. I think this may be the problem.
I will recheck everything and let you know.

Thanks

Gordon...

[Ron Rich]

Gordon,
If the old spring was not compromised, try using it. If not possible, PURCHASE the correct one only ! Ron Rich

[gordo]

Ron,
The old spring was badly bent and reshaped. I will purchase the correct one.
I will let you know the outcome.
Thanks

Gordon..

[gordo]

Hi Ron,

The new spring and grommets arrived. Unfortunately it took about 4 weeks in postage.

Installed today and followed your advice. Oiled the motor and set needle pressure at about 6 grams.

Now all is working well. I am a bit surprised.

Sound no longer wobbles.
I think it was the old spring.
The new spring puts very little pressure on the drive wheel and I had doubts it would solve my problem.

But, straight to 45rpm and did it the job.
Thanks!!!
This jukebox sounds good.

I have a new problem now.
I have some turntable rumble at the start and finish of a record (before the mute cuts in).

Any thoughts?

Kind Regards and thanks once again.

Gordon...

[Ron Rich]

Hi Gordon,
Glad that worked--spring is actually there only to ensure wheel and turntable make contact at motor on--it should not force wheel/turntable contact as that would cause the wheel to get pinched--six grams of needle pressure may be too heavy ? Does the rumble ramp up at the start/end of a record ? If so, AVC in amp out of spec.? Ron Rich

[gordo]

Hi Ron,

I adjusted the needle pressure back to about 4 grams.

The rumble is now much less.
As I don't know if the AVC can be modified, I will leave it for now.

Thanks for your advice.

Regards

Gordon...