TM 32-5835-005-14 & P
board A1A8. This relay is energized
6-4. Logic Circuit, FootSwitch.
during RECORD. The bias oscillator
a. Remote Control Logic. If a remote
output is also connected to the erase
control panel (not supplied) is connec-
head during RECORD to effect erasure
of previous recorded material.
ted to the unit, the push buttons are
connected in parallel with the push
buttons on the front panel and permit
c. Reproduce Amplifier. The follow-
ing discussion will be confined to
unit activation and mode functioning
channel 1 at 1-7/8 IPS. Tape signals,
from a remote location.
from the reproduce head, are switched
6-10.)
through relay K1 to the non-inverting
b. FootSwitch. If a footswitch is
connected (supplied with the unit), the
200 Hz to 8 KHz. Signal-to-noise ratio
rocker switches are connected in par-
improved, the amplified reproduce signal
allel with the push buttons on the
is connected to the input of U1A on
front panel and permit REPRODUCE, STOP
circuit board A1A3 via relay K1 now
During REPRODUCE, equal-
energized.
izers are analog switched by a repro-
6-5. Tape Motion Sensor Circuits.
duce enable signal from the logic
board A1A6. A lesser type equalizer,
a. The End of Tape Sensor Circuit.
located on the record/reproduce board
A1A3, shunts all gain control cir-
sists of an optical motion sensor on
cuitry and the amount of loss is set
the transport module A1A1 and an am-
circuit board A1A5. When the disc on
fied, the reproduce signal is further
amplified by U2A and output stages
the tape supply spool interrupts a
Q1 and Q2. This signal is connected
light beam, the phototransistor sends
a pulse train to rectifier CR1 and Q1
and establishes a DC level across C5.
This turns Q3 on, pulling its collector
ed to a headphone monitor jack A1A2J1.
to ground. If the disc stops turning,
d. Meter Drive Circuits. Rectified
no DC is produced across C5 and Q3
is released from conduction. This
produces a +15 volt pulse across CR4
on the record/reproduce card A1A3 is
and actuates the STOP mode logic on
A1A4. In turn emitter follower Q1
board A1A6.
drives a filter capacitor and resistive
Diode CR1 protects front panel meter
A1A2M2 from burnout.
STOP mode, Q3 receives no base current
drive and, therefore, is nonconducting.
NOTE
If a tape cassette jam occured or
other malfunction that prevents the
The operation of channel 2 is identical
supply reel from turning, no infor-
to that of channel 1. For 15/16 IPS
mation would ever reach the STOP mode
logic. Therefore, each time transport
operation, the record/reproduce amplif-
ier is rolled off sooner than for
brake release is energized a negative
1-7/8 IPS.
going pulse turns Q1 on and, therefore,
Q3's collector will go to ground. If
disc rotation is achieved, the action
described previously will hold Q3 in
conduction. However, if the supply
6-12