Bench Testing a Thorens TD124 Motor

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One more thing

I had a noise problem also when I did my initial tear down and build back up. Since my TT had a cracked original belt, I decided to replace it with a Thakker belt.

Well, very shortly after installing the new belt, I heard more noise rather quickly. After removing the cast iron flywheel, I noticed particles of belt stuck on both pulleys. I cleaned and treated the belt with talcum powder, reversed it, and slipped it back on. I had to do this one more time, and it's been about 2 years since I've had the problem.

To be honest, I cannot recommend the Thakker belt.


Gene
 
What was your noise? Mine frankly sounds like metal-on-metal hiss. It's low, and has gotten much lower since I started breaking it in, but it's a little disconcerting. Just a low-level constant hiss, like a very light scraping.

I'm using the original belt, hard as it is. I have noticed some deposits on the flywheel (although mine appears to be machined aluminum, rather than cast iron) and a corresponding noise increase. I clean the flywheel with some lacquer thinner, and the noise level drops again.
 
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You'll find very quickly that the weight of the lubricants plays a big role in whether or not the machine can be set up to run at the right speed which is what I focus on, cleaning the running surfaces of the pulleys and keeping them scrupulously clean and using a good belt are both key to good speed stability and quiet running.

Obviously bearing condition and alignment play a very large role in both, but I found the hard way that lubricants play a role too.. Very long drive train spin down times usually indicate a too light lubricant and/or badly worn bearings. I look for smooth, quiet operation.. Note the idler can produce all sorts of rhythmic thumping if its got a flat spot or a warp. Warps are not uncommon., but is usually not a problem unless the warp hits the top of the next step on the stepped intermediate pulley.

Check the distance of the magnet from the stepped pulley, unless the magnet is a bit weak you should be good at about 0.2" clearance, but it takes some iterating to get it right..

If you have used very light lubricants or have an extremely weak magnet you may have difficulty getting it to run on speed. Of the two the magnet is the bigger problem.. :)
 
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<snip>

To be honest, I cannot recommend the Thakker belt.


Gene

I second that and wrote extensively here on the problems I have had with belts. The Thakker belt was infuriating as it left a trail of goo on the pulleys within days of installation or cleaning and re-installation - the problem manifested itself as a rising level of noise from the drive train which was severe enough to heard several feet way in a quiet room.
 
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What was your noise? Mine frankly sounds like metal-on-metal hiss. It's low, and has gotten much lower since I started breaking it in, but it's a little disconcerting. Just a low-level constant hiss, like a very light scraping.

I'm using the original belt, hard as it is. I have noticed some deposits on the flywheel (although mine appears to be machined aluminum, rather than cast iron) and a corresponding noise increase. I clean the flywheel with some lacquer thinner, and the noise level drops again.


Sure you are not hearing the eddy current brake, it makes some interesting noise in operation which is very dependent on the version of the stepped pulley fitted, and the distance of the magnet from the pulley.. Generally the more braking action you need the noisier it gets, IMO it should not be audible from more than a foot away.

I assume by flywheel you mean the platter (I think Thorens does call this a flywheel) then it is made from a zinc alloy known as Zamac.. It will appear dull silver except where machined where it will be bright (and possibly a bit corroded). The top platters appear to have been both stamped and spun.
 
I meant the two-sized wheel attached to the motor shaft. I thought the stepped pulley was fairly obvious (the thing over the eddy brake) and I wasn't sure how belt deposits could get on the platter, so I thought we were talking about the same thing.

I honestly have no idea what I'm hearing. I did get the motor itself to be almost completely silent outside of the deck. the noise occurs with the belt attached to both the motor, so my thought was that it was either the strain of the belt on the motor, pulling it against the bearings, or the stepped pulley.

Agreed - it is not audible from more than a foot away, but I had thought that was a fair distance. Glad to have the reassurance.

I am using a synthetic 5W30 motor oil for all of this. I figured since I'm using the old bearings, a slightly heavier weight would be better than the standard 0W20. And my initial readings on the platter spin-down were a little off - when warm, it's closer to 1:10, rather than 1:45.

It looked as though the idler wheel and stepped pulley were greased, rather than oiled, but I cleaned off the grease and used a few drops of oil.

I enjoy the tweakability of this deck, and it should be a great compliment to my LP12. So it's not going anywhere. I plan to see how far I can take this, hopefully on a budget.
 
The noise

JD,

The noise you and Kevin are talking about I believe is the same as I hear on my TD 124 (MK I), and yes, about a foot away it disappears.

The noise does seem to be almost inaudible when there is no load, such as when you remove the main platter (or flywheel).

BTW Kevin, I was getting ready to replace the Thakker belt, when after cleaning it several times, it straightened out, and has been fine for about a year now. It's almost as if it was covered with a gummy substance, but the substance has now worn off. I do plan to try the Ebay guys cheap belt sometime, unless you have a better one in mind, such as the Schopper belt, (which I'm sure is very expensive.)





I honestly have no idea what I'm hearing. I did get the motor itself to be almost completely silent outside of the deck. the noise occurs with the belt attached to both the motor, so my thought was that it was either the strain of the belt on the motor, pulling it against the bearings, or the stepped pulley.

Agreed - it is not audible from more than a foot away, but I had thought that was a fair distance. Glad to have the reassurance.

.
 
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