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Thorens TD124  Serial no. 2729

Above: sn 2729 (sold) standing on its adjuster studs.  Exterior finish is nearly flawless.  See next photos for a complete detail assessment of the deck's cosmetic condition.  The serial numbers were sequential.  Lower numbers indicate earlier production units.  This one, I estimate, would have been manufactured circa 1958 or 59.

DSC_0748.jpg (241881 bytes) DSC_0747.jpg (246304 bytes) DSC_0746.jpg (230229 bytes)

DSC_0744.jpg (202612 bytes) Looking at the nameplate with serial number.

Refurbishment process and upgrades list:

Complete disassembly and inspection of all components.
All parts were cleaned and lubed to insure smooth, correct operation.
rotating parts inspected and measured for evidence of wear.
Main platter bearing received new bushing sleeves (Oilite) in its housing.
Main platter bearing shaft, measured for wear and accepted.  Micrometer checks indicate lack of wear.
Main platter bearing shaft received a silicon nitride ceramic bearing ball at its tip for the renewed thrust.
Main platter bearing thrust pad, replaced with a new Torlon 4301 pad.
A new Heavy Gunmetal bearing thrust cap replaces the original flexy cap.
E50 motor bushings replaced with new.
E50 motor thrust bearing pad replaced with a new Torlon 4301 pad.
MKII motor conversion kit (dual grommet) installed.  I used parts from Schopper in Switzerland for this part of it.  The Schopper grommets are of a new "poly" composition that last longer and isolate better than the original rubber parts.
A new heavy gage power cord. 
Electrical: The "pop" suppressor capacitor was replace with a new one of the same original value.
A new (correct)  replacement neon strobe bulb was fitted.  
The original idler wheel was replaced with a new wheel reproduced by Mirko.  This wheel featured new bushings and a slightly softer rubber composition out at the perimeter where it drives.
The idler wheel thrust washer was examined for wear, found to be in good condition and re-used.
Upper Platter condition:  Straightened.  Clutch operation is correct.  The platter spins without any rub. 

hint: click on thumbnail to view image full size.

Above: Mirko idler wheel.  Machined from solid bronze.  New bushings.  New rubber outer tire.

Adjustments and calibration:

The refurbishment of the TD124's E50 motor requires a multi-step process to assure correct operation.  The E50 in 2729 has received this very high level of care.

DSC_5362.jpg (229973 bytes)

 

mkIIconversionkit.jpg (185410 bytes) E50 with mkII conversion kit.  

Q: How effective is this upgrade?.
A: Significant.  The original (mk1) motor mounting configuration results in signal to noise ratio of -40db.  With the mkII conversion kit, SNR becomes -50db.  This is a difference that can be heard.  Far more detail is described during playback with this simple upgrade.  I consider it to be an essential part of any TD124 refurbishment that I do.

DSC_0741.jpg (321891 bytes) Looking at the underside, while 2729 is fixtured in its service jig.  In this view the Gunmetal bearing bottom cap is prominent.

Gunmetal Bronze Main Bearing Cap: I had a dozen of these machined by a local tool maker.  I sold most of those but kept enough for the turntables in my possession.  2729 has one, of course.

 

DSC_0740.jpg (275887 bytes) 2729 in the service jig and with the upper platter shell and original heavy rubber platter mat.  Note about the mat; It is still quite supple and with no evidence of wear.  

DSC_0739.jpg (250245 bytes) The original rubber pucks on the Iron flywheel have been replaced with silicone gel pads.  I tried these as an experiment.  It is a good upgrade.  I chose to keep these on the flywheel and will install them on future refurbish projects for the TD124.  The result was a slight but noticeable improvement in background silence.

DSC_0733.jpg (285936 bytes) Looking at the underside of the iron flywheel and the main bearing shaft.

DSC_0732.jpg (281712 bytes) DSC_0731.jpg (188994 bytes) And under the hood.

 

BRG_mic_1.jpg (207088 bytes) BRG_mic_2.jpg (204926 bytes)

Above two photos.  Measuring the platter bearing shaft for evidence of wear with a precision micrometer.  

BRGdetail.jpg (111595 bytes) A silicon Nitride Ceramic bearing ball is installed at the thrust end.  A dab of bearing grease is used to retain the bearing ball during assembly.  20 wt. turbine oil is used to lube the shaft and bushings within the housing.  I use an oil formula that is the modern equivalent to that which was advised in the TD124 service manual.  I will include a small bottle (with needle applicator) within the package as part of the deal.

The original nylon sleeve bushings were removed and replaced by Oilite bronze bushing sleeves.  Thorens went to the Oilite bushing sleeves later in the production cycle of the TD124.  For good reason; the Oilite bushings impart little if any wear onto the shaft, and they last long.

After assembly I check that correct operating clearance between shaft and bushing exist in the following manner:

DSC_1828.jpg (106495 bytes) If it rocks more than .001 inches, that's a bit too much bushing to shaft clearance.  And.....the flywheel must spin down free for a long, long, long time.  This unit operates within these limits.

And I also check flywheel for run-out while spinning in its bearing using the same dial indicator.  This one reads extremely close.

Further notes on Motor maintenance: E50

I had a couple dozen Oilite bronze motor shaft bushings machined by a local toolmaker.  2729 has a pair of from this lot.  They were installed during the refurbishment process  Over the years I have opened the motor case to examine for evidence of wear.  The rotating parts and bushings are holding up well.  And operating correctly.

  All bushings manufactured for me are measured 100% for compliance to dimensional limits.  As the photos indicate, I use proper gages for this type of work.

 

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