Overall Operation Of The Deck - Tascam 122 Service Manual

3-9. OVERALL OPERATION OF THE DECK
We have so far seen the separate operations of
control circuits, each with a specific function .
This section briefly describes the overall
l
opera ­
tion of the deck operations in the reproduce,
pause, fast-forward, and rewind modes. Refer
to Section 3-10·3 for operation in the record
mode.
3-9-1 Reproduce mode
See Fig. 3-19.
To explain operations in the reproduce mode,
we divide the system into two subsystems. One
is the head base subsystem that operates when
0601 is turned on by the H-/evel signal output
from pin 12 of U601. The other is the pinch
roller subsystem that operates, when 0602 is
turned on.
1) Head base subsystem
This goes through the following steps when
0601 is turned on.
a. The head base solenoid operates.
b. A delay signal is applied to the pinch roller
solenoid drive circuit via the flashing circuit
of the head base solenoid.
c. 0692 tu rns on and the capstan motor
rotates.
2) Pinch roller subsystem
This goes through the following steps after
a del l ay long enough for the operation of the
head base solenoid following the turning on
of 0602.
a. The pinch roller solenoid operates.
b. The reel motor rotates.
c. The tape-end detection circuit becomes
ready for operation.
d. 0614 turns on and the reproduce amplifier
is released from muting.
Fl60Z
PAUSE
6 IN
II
PAUSE
OUT
C602
l
U601
PAUSE
R613
r
- ' ­
5
R614
3-9-2 Pause mode
To explain operations in the pause mode, we
divide the system into the head base subsystem
(as in the reproduce mode) that operates, with
0601 turned on by the H-Ievel signal output
from pin 11 of U601, and the indicator sub­
system that causes the PAUSE indicator to light
when 0603 is on.
3-9-3 Fast-forward mode
In the fast-forward mode, we divide the system
into the fast-forward subsystem that operates
when an H-' I evel signal is output from pin 15 of
U601 and the fast subsystem that operates when
an H-Ievel signal is output from pin 14 of U601.
1) Fast-forward subsystem
The reel motor rotates.
2) Fast subsystem
a. The fast so lenoid operates.
b. The tapeend detection drcuit becomes
ready for operation.
3-9-4 Rewind mode
In
~he
rewind mode, we divide the system into
the rewind subsystem that operates when a H­
level is output from pin 13 of U601 and the fast
subsystem that operates when a H-Ievel is output
from pin 14 of U601.
1) Rewind subsystem
a. The reel motor rotates.
b. The memory circuit becomes ready for
operation.
2) Fast subsystem
a. The fast solenoid operates.
b. The tape-end detection circu· i t becomes
ready for operation .
STANOARO
HEAD BASE
SOLENOID
L 69Z
+5V
SPEED
54 L...­_ _ _ ...4-~
HEAD BASE SOLENOID
DRIVE CIRCUIT
0514
REMOTE
CONTROL
Fig. 3-20 Schematic of pause mode
24