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  • Author Author: jw0752
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Not Everything is Electronics

jw0752

I have had a Dual 601 turntable for many years, perhaps 50, and it used to work great. Sometime ago it started acting strange as the motor became unstable and would power up and lock on a higher RPM than proper. From the information on the internet it seemed that this was a design problem and would not be easily solved. I tried to fix it anyway. I tried external electronics to see if I could make it come up to the proper speed. I even messed with the pole spacing on the stater but the internet had been correct and it wasn't going to be easy. A friend of mine Eric repairs turntables in his spare time and he offered to watch for a motor from a different model that could be installed with a little modification. When a motor was finally located Eric installed it and brought the table back to me. He mentioned to me at the time that there was a small ferrule that was in bad shape and may fail soon but I didn't pay much attention at the time. The turntable sat for about a month until yesterday when I finally got around to hooking it up and trying it out. The new motor worked like a charm and the speed was solid. When the tone arm got to the center of the record it picked up as expected but it did not return to its rest. It just continued to cycle through lifting and setting back onto the record.

 

I decided to open up the changer and see what was not working. I had the turntable up on pop cans so I could watch the mechanism as it reacted to the end of the record. I turned the table slowly by hand so I could watch what was taking place. There was a small brown ferrule that had cracked in two and was just held in place by the grease on it.

 

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It had a diameter of 0.15 inches a thickness of 0.15 inches and the diameter of the shaft it was mounted to was 0.075 inches. When the record is at the end, the mechanism applies pressure to this ferrule and uses the friction of the ferrule against a moving plate to move the tone arm back to its rest. After some consideration I decided to try to use a nylon screw as the raw material for a new ferrule. The nylon would be an easy material to cut and drill. After a little experimentation and 2 failed prototypes I finally got what I was looking for. Here is the new ferrule mounted to the post that moves the tine arm back to its rest.

 

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If you notice you will see the pop can supporting the turntable so that the mechanism is able to be watched. 50 years ago when I serviced turntable for a living and I had a jig made up so that I could suspend the turntables from the ceiling and work underneath them much as a garage mechanic works under the cars. The trouble with working on turntables is that you can't turn them on their sides or upside down to watch what is going on and it is always difficult to get the vantage point needed to see what isn't doing what it is suppose to. This was a relatively easy fix and it was fun to refresh old memories.

 

Here is the finished product doing what it is supposed to do - playing a Swedish group singing in Spanish to my old ears. Gracias Por La Musica.

 

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John

  • in reply to shabaz

    Hi shabaz,

    That might actually be good news in that there is a chamber between the intake and the turbine that is suppose to allow heavier material, like water, to drop from the air stream. Any dust and dirt would mix with the water mist that gets past the drop chamber and make a paste that would quickly clog the filters minimizing how much liquid water actually got to the motor and impellers. How long has it been sitting since the incident? That may be what killed it. I wish I was there you have my curiosity engaged.

    John

  • in reply to jw0752

    Hi John!

    I've yet to see it, but I was hoping that only some water got to the motor, since it was supposed to be a cyclone type cleaner (i.e. the ones that cost an excessive amount from Dyson) - not that I fully understand how it would behave with water, but I'm hoping the majority of the water never made it through the filter-of-last-resort, but apparently enough did to kill it : (

    I get the feeling with a vacuum cleaner fix, I will still suffer more than the blog readers image

  • in reply to shabaz

    Vacuum cleaners usually have stacked aluminum turbine blades inside a housing. Water has 833 times the density of air so you can imagine the force that is put on the blades when they get a feed of water as opposed to air. You will probably have to replace the motor and turbine assembly unless the water component was mainly mist. A secondary problem will crop up in the near future when the water that may have gotten into the motor bearings causes them to rust and fail. You should blog this repair so we all can suffer with you.

     

    John

  • Hi John,

     

    This is great to see you got it fully functioning again. So much great equipment is thrown out when some effort could fix it.

     

    I have been given a small vacuum cleaner to fix.. ordinarily I'd definitely reject that, but in this case I was really unhappy for the owner, because they'd spent a lot of money on it.. and it had failed because some water got sucked up and it didn't shut down.. for want of a humidity or liguid sensor.