Turntable To Fast

August 12, 2009 5:04 PM

I have a 1970's Panasonic Turntable. I've noticed it runs fast( about 35.25 RPMS). It is motor driven and has been cleaned numerous times. Is it possible that it is just made this way?

Or is there something I can do to bring the speed down? As of now I have a rubber band holding the speed selector a little offset. Any ideas?

posted by tanmandu to media & arts (10 comments total)

Is this with or without the weight of an LP?
posted by OHenryPacey at 5:06 PM on August 12

We'll need a little more info. How about a model number or some pixs?
posted by valentinepig at 5:14 PM on August 12

All turntables are motor driven. Do you mean direct drive as opposed to belt drive?
posted by weapons-grade pandemonium at 5:21 PM on August 12

Assuming this is a mechanical speed selector, peek at the pulleys; at some point in the past, perhaps the belt started slipping, and so someone put a thin rubber band on the motor pulley to help the belt bite. That would change the gear ratio.

Then, I'm not sure how holding the speed selector a bit offset would compensate for that other than through slippage, so is this actually an electronic selector?
posted by davejay at 5:23 PM on August 12

yes I know that if there are not gears in a pulley arrangement; I'm just an idiot
posted by davejay at 5:23 PM on August 12

i give up trying to correct myself. bluh.
posted by davejay at 5:24 PM on August 12

It's possible you have a belt drive turntable made for 50 Hz mains supply, and you are running it on 60 Hz. The fix is to replace the motor pulley with a smaller diameter one made for 60 Hz mains supply, or to cut the one you have to the appropriate diameter dimension on a metal lathe.
posted by paulsc at 9:59 PM on August 12

Seconding paulsc, this is common with older electronics where the power is not regulated, and going from 50hz -> 60hz would result in the motor running fast.
posted by jpeacock at 10:26 PM on August 12

I had a turntable many years ago that started playing LPs a bit too fast. The first two repair places I consulted insisted that this was impossible; that turntables play too slow when something's wrong, never too fast. Finally went to a small electronics shop reccomended by a co-worker. The tech there opened up the turntable and showed me the problem. Rather than being driven by belts, this one was driven by two rubber discs or wheels that rolled against one another. (I hope I'm describing this clearly.) One disc turned against the other disc, and that one turned against the widget that made the turntable spin. The rubber had worn down on one of the discs, making it just a millimeter or so smaller in circumference, which is why the turntable was now spinning just a tad faster. Replacement of the one rubber wheel solved the problem.
posted by Oriole Adams at 10:49 PM on August 12

going from 50hz -> 60hz would result in the motor running fast.

Possible but not likely. Assuming the turntable is using a synchronous motor or servo, 50 Hz would result in 40 RPM, not 35.25 RPM.

I think Oriole Adams is on the right track -- wear on the drive wheels. It would help to know the model number or at least a description of the drive mechanism.
posted by JackFlash at 11:06 PM on August 12