Dual 506-1 Speed Irregularity

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Davids_CA
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Dual 506-1 Speed Irregularity

Post by Davids_CA » 11 Jul 2019 22:35

I was playing a record on my 506-1 a week or so ago, and I noticed it sounded like a slight speed slowdown every so often. I don't recall if it's every RPM or every 1/2 RPM or whatever, but watching the strobe confirmed it. The speed will be perfectly fine, the 'dots' on the platter edge will jump over to the side indicating the speed is slow, and then return to normal. The slowdown lasts maybe a second or so. Imagine playing a record and then putting a finger on the platter edge for a second at regular intervals.
Before I dig into it or order a belt, I'm curious as to what could cause this. I suppose it could be a motor issue as well, but I hope it's something simple! Thanks for any ideas or suggestions.

Solist
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Re: Dual 506-1 Speed Irregularity

Post by Solist » 16 Jul 2019 22:31

Was the 506 serviced before?

Most likely the belt. Be careful where you order the belts. Some sellers literally buy a pack of belts and sell them as replacement for turntables.

Also, check if the belt is rubbing against anything.

I would also suggest cleaning every part that comes in contact with the belt. If its metal you can use isoprohyl alscohol. I think that the subplatter on the 506 is plastic? If its so, I would rather use some warm water, and some very gentle soap (not colored).

Of course remove the piece first, and for cleaning the motor pulley unplug the turntable from the mains.

Davids_CA
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Re: Dual 506-1 Speed Irregularity

Post by Davids_CA » 30 Aug 2019 22:02

Solist wrote:
16 Jul 2019 22:31
Was the 506 serviced before?

Most likely the belt. Be careful where you order the belts. Some sellers literally buy a pack of belts and sell them as replacement for turntables.

Also, check if the belt is rubbing against anything.

I would also suggest cleaning every part that comes in contact with the belt. If its metal you can use isoprohyl alscohol. I think that the subplatter on the 506 is plastic? If its so, I would rather use some warm water, and some very gentle soap (not colored).

Of course remove the piece first, and for cleaning the motor pulley unplug the turntable from the mains.
Ugh, busy summer! I'm just getting back to this. I picked up a Hitachi HT-466 at Goodwill for $30 a couple days after posting this, which has tied me over for a bit. However, I'd like to get the 506-1 sorted out for a second system.

I don't know the history of the Dual; I found it on Craigslist last fall. It belonged to the ex-husband of the seller, and it'd be stored for at least a decade. I can get the belt surfaces cleaned up. Do you have any suggestions as to belt vendors?
Now I have a completely repaired and restored (by Klaus) 1219 on its way back to me. I definitely need to get the 506 in order, as I know I'll have no real interest in it when the 1219 arrives! ;) Thanks!

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