A TUNE-UP FOR THE DUAL TURNTABLE - ThaiHDbox

PHOTO 8: Board with new capacitors.
in doing this job, showing two exploded
parts views, with a photo of the bottom
mechanism and callouts for each point
of lubrication indicating the type of lubricant
to use (Photo 9).
The service manual called for three
brands of lubricants that are no longer
generally available: a high-performance
oil, a silicon lubricant, and a high-performance
lithium-based grease. I had on
hand modern replacements for all three.
For the oil I used Mobil 1, for the silicon
lubricant I used CRC heavy-duty silicone,
and for the grease I used Panef white lithium
grease. I am sure there are many other
modern lubricants that will work as well.
Before beginning the disassembly of
the turntable, I manually ran it through
its cycles while watching the action of the
components. I had to release the tonearm
to do this. All of the mechanism is
driven through a large plastic cam wheel
connected to a gear at the bottom of the
PHOTO 10: Cam wheel rest position.
motor assembly (Photo 10). At rest, the
cam wheel sits with an open space in the
teeth opposite the motor gear.
To begin operation while the motor
is running, a pivoted arm on the cam
wheel moves against the motor gear
which rotates the cam wheel to a point
where its teeth engage the motor gear.
It will continue to rotate until it again
reaches the rest position where there are
no teeth. During that rotation, depending
on the function selected, levers move
through various slots in the cam wheel.
I will not try to describe all the movements
for the different conditions because
you can see them in action better
than I can describe them.
When I was familiar with the operation
of the various parts, I removed the cam
wheel to access the parts that lie beneath.
The wheel is held in place on its shaft by
a “C” clip as shown in Photo 11. After removing
the wheel, I cleaned the old grease
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PHOTO 9: Lubrication points.
PHOTO 11: “C” clip retainer.
from the wheel and applied a new lubricant.
The bottom of that wheel showing
the actuating levers is shown in Photo 12.
Next, I cleaned and lubricated the
assembly that controls the levers on the
bottom of the cam wheel as shown in
Photo 13. Note that one of the levers is
connected to the tonearm and trips the
cycle at the end of record play. That level
must move very freely or there will be
drag on the tonearm. It originally was
“dry”—that is, it had no lubrication. I
did not apply any lubricant to that lever
to eliminate the possibility of drag that
could result from its use.
The assembly shown in Photo 14 is
central to the operation of the arm in
automatic mode and proved to be the
solution to my arm movement problem.
The photo shows a central horizontally
pivoting plate to which are attached two
vertically pivoting arms. The arm on the
left is actuated by the cam wheel and