Sony DTC-A8 / PCM-2600 / PCM-2800 Service Manual ▷ View online
— 82 —
18
17
3
6
MECHA MICON
IC502
5
2
7
1
8
CASSE CON
MOTOR
DRIVE
M54641L
IC523
IN1
IN2
M
OUT1
OUT2
D507
REF
Vcc
Vcc
+6V
+5V
CM-IN
CM-OUT
M1
CASSETTE
COMPARTMENT
MOTOR
Fig. 7-5. Motor Drive (IC523) Input/Output Waveform Timing
Fig. 7-4.
shows the cassette compartment motor drive circuit and
Fig. 7-5.
shows the input/output waveform timings of
the motor drive (IC523) when OPEN and CLOSE operations of the cassette compartment are performed.
When OPEN operation of the cassette compartment is performed, Pin !• (CM-IN) of the mechanism microprocessor
becomes “L”, “H” is output from Pin 2 (OUT2) of the motor drive (IC523), and the cassette compartment motor (M1)
rotates in the reverse direction.
In CLOSE operations, Pin !¶ (CM-OUT) of the
mechanism microprocessor becomes “L” and Pin 7
(OUT1) of the motor drive becomes “H”.
Pin 5 (REF) is an output voltage control pin and is
composed of the internal circuit shown in
When OPEN operation of the cassette compartment is performed, Pin !• (CM-IN) of the mechanism microprocessor
becomes “L”, “H” is output from Pin 2 (OUT2) of the motor drive (IC523), and the cassette compartment motor (M1)
rotates in the reverse direction.
In CLOSE operations, Pin !¶ (CM-OUT) of the
mechanism microprocessor becomes “L” and Pin 7
(OUT1) of the motor drive becomes “H”.
Pin 5 (REF) is an output voltage control pin and is
composed of the internal circuit shown in
Fig. 7-6.
The same potential as that added to Pin 5 is output
from Pin 7 (OUT1) or Pin 2 (OUT2).
In the case of this unit, as the Vz=5V Zener diode
(D507) is connected, the OPEN/CLOSE operations
are made to end in approximately 870 ms.
from Pin 7 (OUT1) or Pin 2 (OUT2).
In the case of this unit, as the Vz=5V Zener diode
(D507) is connected, the OPEN/CLOSE operations
are made to end in approximately 870 ms.
Fig. 7-6. Internal Circuit of Output Voltage Control Pin
Fig. 7-4. Cassette Compartment Motor Drive Circuit
— 83 —
7-3. Tape Loading and Eject Operations
Fig. 7-7
and
Fig. 7-8
show the timings of the detection switch and the loading and cassette compartment control output
when the tape is loaded and CLOSE or EJECT operation is performed.
When a tape is loaded and the CLOSE button is pressed, Pin !¶ (CM-OUT) of the mechanism microprocessor becomes
“L”.
As a result, the cassette compartment (M1) rotates normally and the cassette compartment CLOSE operation is
performed.
When cassette compartment CLOSE operation (approx. 870 ms) end, the cassette compartment LOCK SW (S11) turns
ON and Pin !¶ becomes “H”, the motor drive (IC523) sets into the brake mode, and the cassette compartment motor
stops.
After this, Pin !∞ (LM-EJECT) becomes “L”, the loading motor rotates normally, and loading operations start.
The detection of completion is performed when the LOAD SW (S903) turns ON. The brake mode is set in the same way
as the cassette compartment motor drive circuit and the loading motor stops.
During EJECT operation, immediately after the EJECT button is pressed, Pin !§ (LM-LOAD) becomes “L”, an unloading
operation is performed, and when unloading completes, Pin !• (CM-IN) becomes “L” and cassette compartment OPEN
operation is performed.
The completion is detected, when the UNLOAD SW (S902) and cassette compartment OUT SW (S12) turn ON.
When a tape is loaded and the CLOSE button is pressed, Pin !¶ (CM-OUT) of the mechanism microprocessor becomes
“L”.
As a result, the cassette compartment (M1) rotates normally and the cassette compartment CLOSE operation is
performed.
When cassette compartment CLOSE operation (approx. 870 ms) end, the cassette compartment LOCK SW (S11) turns
ON and Pin !¶ becomes “H”, the motor drive (IC523) sets into the brake mode, and the cassette compartment motor
stops.
After this, Pin !∞ (LM-EJECT) becomes “L”, the loading motor rotates normally, and loading operations start.
The detection of completion is performed when the LOAD SW (S903) turns ON. The brake mode is set in the same way
as the cassette compartment motor drive circuit and the loading motor stops.
During EJECT operation, immediately after the EJECT button is pressed, Pin !§ (LM-LOAD) becomes “L”, an unloading
operation is performed, and when unloading completes, Pin !• (CM-IN) becomes “L” and cassette compartment OPEN
operation is performed.
The completion is detected, when the UNLOAD SW (S902) and cassette compartment OUT SW (S12) turn ON.
Fig. 7-7. Input/Output Waveform Timing during CLOSE
— 84 —
Fig. 7-8. Input/Output Waveform Timing during EJECT
— 85 —
7-4. Plunger (PM) Driver Circuit
Fig. 7-9. Plunger Driver Circuit
Fig. 7-10. Plunger Drive Timing
The mechanism section is equipped with the brake plunger (PM901, this plunger is included in the reel motor M903)
which turns ON/OFF the T/S reel table brakes and the FWD plunger (PM902) which carries out compression/release of
the pinch roller. They are driven by the driver circuit shown in
which turns ON/OFF the T/S reel table brakes and the FWD plunger (PM902) which carries out compression/release of
the pinch roller. They are driven by the driver circuit shown in
Fig. 7-9.
In the case of the FWD plunger, Pin !‚‚ (FPM-
ON) of the mechanism microprocessor (IC502) outputs “H” as shown in
Fig. 7-10.
during driving, and at the same time,
approximately 50 ms kick pulse is output from Pin 1 (FPM-KI).
As a result, an approximately 13V is added to the plunger, and the pole piece is sucked and the pinch roller is adhered.
When the kick pulse ends, the plunger is maintained by the 2V supplied to it via D505 so that power consumption is
reduced and heat from the plunger is controlled.
As a result, an approximately 13V is added to the plunger, and the pole piece is sucked and the pinch roller is adhered.
When the kick pulse ends, the plunger is maintained by the 2V supplied to it via D505 so that power consumption is
reduced and heat from the plunger is controlled.
D505
Q505
Q509
FPM-ON
+5V
Q504
PM902
FWD PLUNGER
+2V
+13V
FPM-KI
Q511
100
1
MECHA
MICON
IC502
IC502
mechanism
microprocessor
mechanism
microprocessor
Approx. 50 ms (PM kick)
Click on the first or last page to see other DTC-A8 / PCM-2600 / PCM-2800 service manuals if exist.