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Old 1st November 2010, 02:26 AM   #71
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Thanks for the reply. In the interim, I succeeded by using a crummy gear-puller that I had bought for another job. Now, on to the rebuild.

Kal
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Old 1st November 2010, 03:35 AM   #72
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TD-124 in its temporary plinth. This plinth is a very light weight plywood affair and as a result I am using the gel bushings as I doubt that this plinth will do much to absorb and dissipate vibration from the deck..

Tonight I also discovered that purchasing a Thorens branded belt from Thakker is no guarantee that you are getting a functionally equivalent belt to the original. The original belt was in good condition and as it turns out the new belt has stretched to about the same exact length as the original. The original however is much more compliant, and a lot thinner. The new belt measured 0.036" thick and the original 0.021" quite a difference - and the old belt runs much quieter, night and day in fact. This is not really good news because 43yr old belts generally don't have long service lives, but this may help me to locate a more suitable belt.
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Old 1st November 2010, 04:13 AM   #73
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Default Heat Wrench

Quote:
Originally Posted by Kal Rubinson View Post
Do you have any suggestions about removing the motor pulley? I have loosened the two set screw on the shaft but the pulley is still firmly on the shaft.

Kal
One other way to persuade the pulley to come off is to judiciously apply heat using a pencil butane torch such as the type used for portable soldering. In the absence of that, a propane torch with a small tip could be used sparingly. The heat will cause the pulley to expand and free it up from the shaft. If it is really stubborn, apply heat several times allowing it to cool off befroe reheating. This should allow it to free up without the risk of damaging the pulley by prying with excessive force. Just be careful not to apply excessive heat which could damage the insulation on the wires of the armature, but given the mass of the armature, it would take a lot of heat.
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Old 1st November 2010, 04:19 AM   #74
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This is a shaded pole induction motor, I am not sure what insulation if any is used in the squirrel cage in the armature, the windings in the stator assembly however can be damaged by heat. The force required to separate the pulley from the shaft is minimal in any event.

When reinstalling the pulley make sure you tighten the black grub screw first and the silver one last. I couldn't tell any difference, but I'd follow the recommended sequence anyway.

The final thing I would say is that unless the original belt is useless I would use it instead of any of the current production belts which seem to cause a needless increase in noise level.

Order an FM12.1 belt from here: http://www.turntablebasics.com/beltmodels.html - at least it appears to be correct in ways where the replacement Thorens belt is not. The old belt was approximately 12.8" circumference (this is approximate) and 0.021" thick, the replacement Thorens is 0.036" and far too stiff, it also costs 3.5X as much and is a poor performer. The FM12.1 is 0.023" thick and all else being the same should be more flexible. I've ordered one to see if it actually fits the bill.
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Old 1st November 2010, 05:03 AM   #75
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Default Pulley and Belt

Good to know that the Thakker belt does not seem to be as advertised. I was considering ordering one and paying the premium for a supposed exact replacement. It appears not to be so and now I can save money for other stuff.

The armature may have some varnish as insulation to minimize eddy currents so there is a chance that it could be damaged by heat. I would not worry about the stator given its mass and the only heat conduction would be through the small surface area of the bearings. If the pulley comes off with minimum force then no problem or need for heat. If it is really stuck, that is another story. With dissimilar materials, corrosion can get pretty severe. Should be no real problem with the Thorens motor and pulley, though.
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Old 1st November 2010, 05:14 AM   #76
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Quote:
Originally Posted by GTHICM View Post
Good to know that the Thakker belt does not seem to be as advertised. I was considering ordering one and paying the premium for a supposed exact replacement. It appears not to be so and now I can save money for other stuff.
<snip>
Just wish I wasn't the one who had to figure this out.. LOL There has been a lot of commentary at VE and elsewhere around the web about this issue, but apparently doing a little investigation and then using Google to find the right belt is just soooo hard..

I unfortunately wasted $35 + S&H, but hopefully this turntablebasics.com belt will turn out to be what I expected. Interesting that they do at least disclose the full dimensions of the belt. I wish they included the durometer of the belt as I believe this is rather important as well. Presumably having figured out that the belt thickness was important, they probably choose an appropriate durometer as well.

It should make a big difference. My original belt seems to be in very good shape, but it is 43yrs old as a minimum so having a good replacement on hand would be reassuring.

I have also been investigating bearing end caps, and I noticed that all of these fancy gunmetal and bronze ones have poorly finished internal surfaces and since they are mostly not used with thrust plates this is a concern I think. There is one stainless steel kit with thrust plates included which also happens to be the least costly choice and I am debating it.
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Old 1st November 2010, 09:09 PM   #77
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I now have someone insisting on another forum that there are in fact two different belts for these TT based on whether or not they are set up for 50Hz or 60Hz, however I can find no evidence of this at all in Thorens literature, but were I buying for a 50Hz table I would probably get a slightly longer belt.

Interestingly enough the part number for the MK1 and MKII belts are different as are a number of other parts in the drive train, but no information beyond that. (CB965/CB908 respectively)

He went so far as to insist that the belt originally installed on my North American spec TD-124 was actually for the European version. I don't believe it for a moment as were that truly the case it would be so loose it would be falling off, and the original seems to fit nicely and run quietly. Hopefully I have found something that will work to replace it from turntablebasics.

There is a lot of really inaccurate information out there about the TD-124, and I am developing a healthy dose of skepticism about what I read online about this and other things I have direct experience of..

It really looks like I have to figure it out myself and make some mistakes along the way.
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Old 2nd November 2010, 12:18 AM   #78
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Does anyone know the diameter of the ball bearing that sits in the bottom end of the motor shaft of the E-50 motor? Apparently, someone (could have been me) let it loose in an earlier examination of the motor and I need to get a replacement. I have heard suggestions of .078" and .080".

Kal
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Old 2nd November 2010, 12:22 AM   #79
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Default Belt Sizes and Misinformation

I would have to agree with you, Kevin, as to the amount of misinformation on the internet concerning this and other audio gear. There are some well respected individuals who advocate the use of grease in oilite bearings, for example, as well as the puffing in advertizing respecting upgrades and modifications.

I will have to change the pulleys on my Thorens TD124 MkII for 50 Hz operation, so the belt issue is something I looked into a bit. The official parts list and service manual for this turntable makes no mention of different belts for different frequencies. Turning to the Schopper website, probably the best source for restoration and parts sourcing for the TD124, they list one belt and specifically state it is for both 50 and 60 Hz operation. Given all this, the objective conclusion is that there was and is only one proper belt for the TD124. Others may have seen different belts on these units, but over the decades, there would have been many parts replacements, and not all proper.

As you have said, one has to learn for themselves. Research helps, but one cannot stop there. Thanks for sharing your experiences with this project. It helps all of us struggling with the same issues.
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Old 2nd November 2010, 01:42 PM   #80
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Quote:
Originally Posted by Kal Rubinson View Post
Does anyone know the diameter of the ball bearing that sits in the bottom end of the motor shaft of the E-50 motor? Apparently, someone (could have been me) let it loose in an earlier examination of the motor and I need to get a replacement. I have heard suggestions of .078" and .080".

Kal
Hi Kal,
I have heard of others using anything within the range you cited above. Some bearing service kits on eBay include the ball bearing.. I figure a silicon nitride ball bearing would be the cat's meow here, but remember to turn over the thrust plate when you service the bearings.
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