Marantz cp430 - Alignment Points

4. MECHANISM AND CIRCUIT DESCRIPTION
4.1 Muting System
The muting circuit is provided to reduce the pops noise
when generates on the Line Out at power ON/OFF.
1) When power is turned on.....
As the base voltage of QUO3 is higher than the emitter
voitage during the charge current flows to QUO2 through
RUO3 & RUO2, QUO3 is ON and it sends the muting
voltage.
CUO02 have been charged up, both the base and the
emitter voltages of QUO3 is equal. QUO3 is OFF and the
muting is released.
2) When the STOP button is depressed... ..
When the stop switch S073-1 is ON, the base current
flow through DUO4. Also discharging CU02, QUO3 is
ON instantly, the muting system operate to reduce the
Pops noise at power ON/OFF.
DMO2 provides to discharge CU02 on AUTO STOP.
As the muting time is in proportional to capacitance of
CU02, it is presetted by matching the threshold time of
TAPE EO Amp.
Vee
High Volt
Line
4.2 Auto PLAY and Automatic Rewind Stop
With SS01 set to ON during PLAY, the rewind button wit!
lock when pressed. When counter reaches 999, the rewind
lock releases and the PLAY operation resumes. In this
condition, both CUE and REVIEW buttons do not operate
and both buttons are locked. Also, when the FF button is
pressed and locked in place, the lock releases when the
counter reaches “900” and the PLAY mode is entered. When
the tape has finished winding in both modes before the
counter reaches the respective positions, the AUTO STOP
function and all buttons are released. Also when the RE-
WIND button alone is locked, the tape rewinds and rewind
stops when the counter reaches ‘999’, The same applies
for fast foward operation which stops at ‘900’. When the
counter is between “900” and “999’’. both REWIND and
FF bottons do not lock.
4.3 Auto Stop
The AUTO STOP function which detects the end of the
tape is carried out by hole IC (QMO8). The signal from
QMO08 is added to the pin @ of QMO7, while the auto stop
duration is designated inside QMO7. The time it takes for
the auto stop function to activate after the tape stops,
is determined in CMO8. At this time TE is TE = 75 X
CM08 (uF)mSec, while TW is TW = 30 X CMO7 (uF)
mSec as long as the auto stop function is operating. When
it does not shut off the first time, TE--Tw-TE--TW is
repeated until it shuts off.
4.4 Pitch Control
The
pitch
control
is
used
to
vary
the
tape
speed
for
play-
back
operation.
During
recording,
it
is
automatically
set
to
the
RSO6
center
position
by
SS01.
RSO6
ssor
Rec «—~ Play
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