Assembling the new idler wheel
A new idler wheel was supplied by Mirko Djordjevic **. Build quality is excellent. Price is reasonable. The rubber is identical to the originals I've seen. I do notice a couple of differences between the idler wheel supplied by Mirko and the original part. Firstly, the metal appears to be brass/bronze, while the original wheel is steel. Then look closely at the bushing. It appears to be a press-in bushing like the original, but the bushing of Mirko's idler wheel is not Oilite bronze like the original. Consequently, this idler will require a little bit of lubrication every now and then.
Upon assembly I noticed that I needed to adjust elevation of the idler wheel downward for correct engagement of the stepped pulley capstan. This was easily done by loosening the two set screws of the idler bracket next to the cam ..................
...........and re-positioning the cam follower shaft until I had approximately 1/64th inch gap off the adjacent shoulder of the stepped pulley. (CB1351)
Viewing the other side of the new idler wheel.
Lube to the axle. Note that the original nylon thrust washer and phenolic
shim are in place.
With the wheel over the pin
With the phenolic washer
With the retainer installed. The service manual suggests to allow 1/64th
inch of free play between top of idler wheel and the locking collar above
it. It isn't necessary to tighten the set screws of the lock collar very tight. Just a little bit does it. The
open slots of the set screws are easily torn off by aggressive screw driver
behavior.
Assembling the rest
The original voltage sticker had lost adhesion and peeled off the chassis. Rather than attempt to
stick it back down with "who knows what" adhesive, I chose to scan the
intact sticker into Photoshop and print out some new stickers on inkjet transparency
(clear) with adhesive backing. It is a pretty close facsimile, if I do say so
myself...;-)
Platter Bearing
New Oilite bushings have been installed. A heavy gunmetal bronze end cap
replaces the original flexi-cap. A new Delrin thrust pad.
Looking ready to go but not quite.
Filling the bearing housing with Texaco R&O 46. A 20 wt. turbine oil
of the same specification as the original. Oil is filled level to the top
of the lower bushing. Then when the platter with bearing shaft is
installed, the oil will be displaced up to the top of the housing to lubricate
the shaft and bushing in that area. This is a case where too-much oil is
better than not enough. Excess lube will spill out the top of the housing
and into the chassis. If that happens, just mop it up.
Silicon Nitride Ceramic bearing balls. Diameter is 6mm. I sourced these
from Boca Bearings. Price is reasonable.
A shot of the ceramic bearing ball placed into the countersink at the shaft
end. I use bearing grease to hold the ball in place while assembling.
Note that later TD124 bearing shafts use a retainer clip to hold the bearing
ball in place. The really early models, like this one, don't have
that.
Having fitted the bearing shaft into the housing, we're now waiting for the platter to descend all the
way down. It takes about 5 - 10 minutes. When the bearing ball
touches the thrust pad it will look like the photo below. Also, note the
weathered surface texture on the center spindle. This was lightly touched up by
holding ultra-fine wet/dry (#1200) against it while spinning at 78 rpm. The result
of the clean-up can be seen in the photo below.
Adding some lube to the spindle pin for the bronze bushing of the outer shell
platter. Just a little bit. Excess oil will be wiped off after the
shell has been fitted and then removed.
Next: Listening
Footnotes:
** Mirko Djordjevic can be reached at: cary300b@hotmail.com for more info about is oem turntable replacement parts.