Akai GX-747 dbx Service Manual page 22

MON REV
SW P.C Board SWl
--
Sensing L Sensing Pole L
Sensing R
Sensing Pole R
REV detection RL6
SW908
Take up side tension arm, detection of shut-off position
SW907
Take up side tension arm, detection of arm lock position
I
SW906
Supply side tension arm, shut-off position
SW905 Supply side tension arm, arm lock position
Reel size SW903
Track selector Pre Amp SW3
Tape Speed Tape Speed SW
UP/DOWN
Counter P .C Board SW3
4-2-2 TENSION ARM LOCKING SYSTEM
(Refer to Figs. 6-32 to 6-35)
The tension arm position is detected by means
of the microswitch. At the time of shut-off, the
tension arm is placed in locked position by the
release motor. If any function key (FWD, REV,
Truth table of BA6109 (IC 5, 6)
Fig. 6-31
FF or RWD) is pressed when the tension arm
is in the lock position, the release motor starts
and after the arm comes to its middle position
(i. e., the tape is loaded), such outputs as listed
in Fig. 6-29 will be issued from the terminals
of ICl.
INW Pin
IN@Pin V Out 1G) Pin VOut 2 @Pin
H
H L L
L
H
L
H
H L
H
L
L
L Open
Open
Fig. 6-32
ARM POSITION
WHEN TAPE IS LOADING
SW9O8
SW9O5
0
SW907
Fig. 6-33
SW positions in accordance with the tension arm positions
Position of tension arm
SW905 SW906 SW907 SW908
Lock
off ON off 0:-i !
Middle ON off ON off
Shut-off
off off off of
Fig. 6-34
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