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Old 13th October 2010, 08:48 PM   #41
Pano is offline Pano  United States
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I'm keeping an eye on your project. Cool work you're doing.
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Old 14th October 2010, 12:29 AM   #42
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by panomaniac View Post
I'm keeping an eye on your project. Cool work you're doing.
Glad to hear that, and without further ado, here are some more pix..

You can see the drive train in various states of disassembly. Everything was thoroughly cleaned and then lubricated prior to reassembly.

The Eddy current brake was suffering from dried out lubricant so I removed it and cleaned all of the sliding surfaces and then lubricated with teflon grease and reinstalled. Works perfectly and needed no re-adjustment.

The motor came apart fairly easily, used a combination of "modified" (read ruined for anything else) and small adjustable wrenches. The hardest part was actually removing the pulley..

One area where I may not have done a good enough job is with the pulley positioning mechanism. The lubricant had turned to glue and I removed what I could without fully disassembling it - it works but takes its sweet time engaging particularly when it is cool down here. I need to take it apart and clean it properly and relubricate it to solve this issue.

The motor was run in and tweaked over a period of 3 hours before re-installation. The bearings and felts are new, 20wt electric motor oil was used to lubricate the bearings. The felts were thoroughly impregnated with this oil before assembly which is EXTREMELY messy.. The motor was loosely assembled and alignment tweaked for lowest noise and then run..
Attached Images
File Type: jpg disassembly1.jpg (323.8 KB, 793 views)
File Type: jpg disassembly3.jpg (328.9 KB, 766 views)
File Type: jpg motor5.jpg (403.3 KB, 759 views)
File Type: jpg motor_running_reduced.jpg (755.0 KB, 754 views)
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Last edited by kevinkr; 14th October 2010 at 12:42 AM.
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Old 14th October 2010, 12:36 AM   #43
Pano is offline Pano  United States
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Very nice! That brings back memories. Had forgotten all about the eddy brake.
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Old 14th October 2010, 12:37 AM   #44
kevinkr is offline kevinkr  United States
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Here are some more pictures of the table going back together..

Shots showing the restored motor with new gel bushings installed, table without and with motor.

Getting ready to install belt, pulley and retainers.

Check the position of the motor drive pulley with the belt installed before installing the brake/drive pulley retainer, and idler pulley.

Note that the material in the main bearing is a laboratory grade lintless wipe - you do NOT want to use paper towel here!

The lubricant used is "3 in 1" brand special motor oil 20wt which was recommended by a number of people who work on these tables, and I used it everywhere the old Thorens oil would have been used..
Attached Images
File Type: jpg motor_mount.jpg (714.2 KB, 729 views)
File Type: jpg motor_ready.jpg (421.2 KB, 355 views)
File Type: jpg With_motor.jpg (411.4 KB, 321 views)
File Type: jpg beltless.jpg (686.6 KB, 331 views)
File Type: jpg belted.jpg (396.1 KB, 333 views)
File Type: jpg ready to run.jpg (423.3 KB, 302 views)
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Last edited by kevinkr; 14th October 2010 at 12:43 AM.
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Old 14th October 2010, 12:49 AM   #45
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by panomaniac View Post
Very nice! That brings back memories. Had forgotten all about the eddy brake.
Before solid state electronic controls* shaded pole synchronous motors and eddy current brakes were the most economical way to control speed. It's kind of primitive and consumes a significant amount of torque as the motor with no brake applied will be running about 3% fast - this brake has a total range of 6% (+/- 3% of nominal)

Note that the zinc/aluminum platter supposedly fitted to a limited number of MKII turntables apparently seemed to be fitted more often than not for the North American market. I've seen several and they all have this non-magnetic platter. Mine is very late so perhaps the iron platter was no longer being made by this point?

I'm planning to save my pennies for a Schopper replacement platter if I really like the end result of all of this work. ( This is a non-magnetic high density iron platter that Thorens would have used back in the day if the materials had been economically viable) We'll see as it is rather expensive - I would have to be completely committed to this table first.

Note that when refilling the bearing do NOT overfill it! Add a little at a time, add too much and if your bearings are in excellent condition the spindle will NOT seat in the housing as the oil cannot escape. I discovered this to my considerable chagrin and had to remove a lot of oil after filling the bearing housing too full. The gaskets on late MKII seem very tough as well, probably not universally the case.

It will be getting a very nice plinth sometime in the near future.

* Fairchild had an electronic, all tube drive for one of its turntables back in the late 1950s. Some Fairchild transcription/broadcast turntables still perform at levels that are hard to achieve today. (They're rare and some models are expensive.)
Attached Images
File Type: jpg sorta_running.jpg (426.9 KB, 350 views)
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Last edited by kevinkr; 14th October 2010 at 01:03 AM.
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Old 14th October 2010, 02:23 AM   #46
limono is offline limono  United States
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I put Music Maker III on Grace 707 today and have to say that results are quite wonderful. It is a very musical combo and I'm not surprised that people tend to blend idlers with heavy arms SPU carts to slow down a little the rythmic pace of those tables.Rega/benz still have an edge on staging/imaging ,bass but idler is really fun to listen.Based on my short exposure to SME TT (I actually heard twice top SME table with Jan Allerts cart and fell in love with Maria Callas) you'll have quite a bit off fun with this table (I'd compare it to drinking moonshine and getting acquainted with country girls
Nice work!!
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Old 14th October 2010, 05:06 AM   #47
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by limono View Post
I put Music Maker III on Grace 707 today and have to say that results are quite wonderful. It is a very musical combo and I'm not surprised that people tend to blend idlers with heavy arms SPU carts to slow down a little the rythmic pace of those tables.Rega/benz still have an edge on staging/imaging ,bass but idler is really fun to listen.Based on my short exposure to SME TT (I actually heard twice top SME table with Jan Allerts cart and fell in love with Maria Callas) you'll have quite a bit off fun with this table (I'd compare it to drinking moonshine and getting acquainted with country girls
Nice work!!
Hi Limono,
The Grace 707 as I recall is on your TD-124? Sounds like a good combination has been found at last.

I'll be running mine with an SME 3009 Series II initially and may purchase one of those 3012 conversion kits off of eBay at some point to convert one of my several arms.. The cartridge will be a Zu/Denon DL-103 which is almost half the mass of an SPU G series cartridge..

Still have a few issues to resolve with idler wheel engagement - I should have removed the mechanism and cleaned the pieces better as it needs a little persuasion to engage.

I also noticed that I put the platter back on a bit eccentric, and turns out this is super easy to fix.

I am amazed at how quickly it comes up to speed on 33/45 rpm, it is extremely quick, 78 rpm takes a bit longer. Motor is rated at 15W..
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Old 14th October 2010, 05:22 AM   #48
kevinkr is offline kevinkr  United States
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Originally Posted by kevinkr View Post
Heard today from the eBay seller of the many rebuild parts I bought for the TD-124, they are all in and the parts will ship this Saturday..

Recent massive multiple computer failures means I have two computers to rebuild before I can start the next phase of the TT project, but I will document and photograph at least some steps along the way once I do get going.
I'm still waiting for the parts for one of the two computers, but figured I needed something to do in the meantime. I want to spend some time soon with a certain 219 tone arm.. I'm still very PC challenged as the media server parts despite being ordered 4 days later than the desktop got here in 2 days, the desktop parts will probably be here next week.. Will jump back on the PC thing when I can, in the mean time I'll enjoy my originally planned audio tinkering..
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Old 18th October 2010, 12:45 AM   #49
kevinkr is offline kevinkr  United States
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Some computer issues resolved, others not.. argh.. Which brings me to the Thorens..

I have been running it a lot, basically whenever I am down here in the basement. The motor is now very quiet, however there are plenty of other things to go wrong, which have, fortunately none too serious..

First I was horrified to hear a loud ticking coming from the TT that sounded just like a flat spot on the idler pulley.. I looked at it very carefully and could find no flat spot at all even under a magnifying glass, running a finger nail over the running surface of the idler revealed a bump which turned out to be some foreign object that somehow glued itself to the circumference of the idler.. (Easily removed)

Second is a strange scraping noise coming from the intermediate pulley which seems to indicate that it might be rubbing the top of the bearing assembly and needs a minor adjustment - further investigation required.

The fact that the motor runs at 1800rpm might also imply that there is a 30Hz noise component in the motor noise spectrum, not to mention the audible 60Hz winding hum.. Wondering about that..

There are a multitude of noise sources in this TT that no belt drive has to deal with - two additional bearings and the interfaces between the intermediate pulley, idler, and platter.. The intermediate pulley probably would benefit from some damping, but there is very little area where it can be applied due to the the eddy current brake, and clearance between idler and intermediate pulley at 78rpm. Seems like a thin coat of aquaplas on top would be as ideal as possible, but where to get it?

The platter rings like a bell which is a major concern as well. I may try a coating or some matting..

For those who can read Italian or run it through a translator this Italian site has some interesting insights into the TD-124 MKII motor at audiosilente.com: Sugli avvolgimenti del 124 He sacrificed three good motors to determine that there was in fact a difference in motor winding construction between the MKI and MKII.. Note that he also claims to be able to make nearly identical windings for potential replacements and/or upgrades. This is probably a better option frankly that a Papst Aussenlaufer replacement motor unless you can provide 3 phase drive for it. It would appear from my limited observations that his allegation that they redesigned the windings for the E50 used in the MKII for more torque is true, mine comes up to speed extremely quickly. The MKII motor in my table is rated at 15W compared to the MKIs I've seen which are rated at 10W.

I guess listening is going to where it's at, because as I tinker with the table I can see it has a lot of mechanical vulnerabilities later designs don't. Design execution and my ability to restore it are going to determine just how much of a actual handicap these theoretical disadvantages prove to be. (If the mechanical noise floor is sufficiently below the medium's own noise floor who cares?)
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Last edited by kevinkr; 18th October 2010 at 12:56 AM.
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Old 18th October 2010, 02:34 AM   #50
limono is offline limono  United States
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I think you're obsessing too much about this table. The reality is, with the big motor, belt and idler wheel it is going to be a noisy clunker no matter what I'm quite sure it won't match SME table in any area but it will be fun to listen .I'd just stick the table in some butcher block plinth, set up an arm and give it a listen before you invest any more in the machine.I think you will hear right away if it's worth pouring more money into it or not.
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