Marantz CD-73 - 3.2 Remote Control Circuit; 4. ADJUSTMENT PROCEDURES FOR DISC CLAMPER; 4.1 Adjusting the height of the pressure ring holder

3.2 Remote Control Circuit
A. Outline of the system
Marantz Bus System is a general term to this remote
contro! circuit. Remocon transmitter and remocon
receiver are necessary to operate it.
The output of the remocon receiver is connected to the
remocon “IN” terminal on the rear panel of the CD-73.
The remocon transmitter has 4 keys for play/next,
puase, repeat and stop.
B. Operation of each part
a) Q851 is N channel Micro Processer for remocon.
b) Q857 amplifies a signal from the remocon receiver
and transmits it to pin 24 of the Micro Processer.
c) O858 is a transistor switch. When a laser signal ‘“S”
becomes Low level, it switches ‘“‘ON’’ and changes the
Micro Processer pin 25 to High level to generate an
easy operation signal at pin 19.
This easy operation signal is reversed at Q856 and put
out from the easy “OUT” terminal of the CD-73.
This signal makes easy operation possible.
Q853, Q854 and Q855 are used as analogue switches
and controled by output pin 9, 10 and 15 respective-
ly. Q852 is a transistor switch, which lowers a sense
signal to GND level to stop operation.
R852/D851/C856 are used for initial setting of the
Micro Processer.
d
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e
C. Overall operation
When any key of the remocon transmitter is pushed, a
pulse signal is transmitted to the CD-73 remote “IN”
terminal through the remocon receiver. This signal is put
into the Micro Processer pin 24 after being amplified at
Q857 and the Micro Processer comes to correspond to
the key to generate High signal at the output pin as
follows.
play/next ........ ping
pause ........... pin 10
repeat... ......... pin 15
STOP s(inane eae 4d pin4
Besides, only when the play/next key is pushed, an easy
Operation signal occurs at pin 19 for 60 msec to mute
the other sources.
m 3588
4. ADJUSTMENT PROCEDURES FOR
DISC CLAMPER
4.1 Adjusting the height of the pressure ring holder
The height of the holder must be adjusted to maintain
braking by keeping the appropriate distance between the
holder and pressure ring.
With the drawer in the unit, lift the holder manually, and
place the positioning tool on the turntable.
If the drawer is in the “out” position, the alminum cap will
come in contact with the front chassis and front panel, and
will be scratched when the drawer is pushed into the unit.
With a screwdriver, turn the adjustment screw clockwise 2
or 3 turns. Push down the holder several times to confirm
that it sinks a few milimeters until it makes contact with
the positioning tool. If there is no play between the holder
and tool, turn the adjustment screw further until a few
milimeters play is obtained.
Turn the adjustment screw counterclockwise until the play
between the holder and tool becomes zero.
For optimum adjustment, do not exert excess pressure on
the acdiustment screw with the screwdriver.
Apply lock paint to the adjustment screw.
Lift-the holder with the drawer in the “in” position, and
remove the positioning tool.