TM 32-5835-005-14 & P
the STOP lamp indicator and brakes.
motor for this hold-back tension.
Thus, U2 provides a memory for the op-
Pressing the RECORD switch places a
erator commands. Q6 enables the search
logic high on SB of U2 (See Figure 6-7).
potentiometer A1A2R4 in FAST FWD and
The RECORD switch contacts receive
REWIND. In all other modes, the search
their source voltage from the PLAY
potentiometer does not affect the reel
switch via CR14 and CR13. Therefore,
RECORD cannot be activated until PLAY
driver transistors. In RECORD and PLAY
is activated. The action, however, of
the take-up reel motor is partially en-
ergized due to the Zener action of VR1.
PLAY and RECORD is to reset one another.
In FAST-FWD, the take-up reel motor is
To prevent this, C10 is provided on the
fully energized; REWIND is the only
RECORD switch input and receives a
mode that energizes the supply reel
charge when PLAY and RECORD are pressed
motor.
simultaneously. Because the S inputs
over-ride the R inputs for as long as
j. Record/Reproduce Control Logic.
they are both high, the signaling
Pressing the REPRO switch places a
appears at the output of U2 on both QA
and QB. QB output at once returns the
logic high on SA of U2 and resets all
RECORD lamp indicator to ground, there-
other functions (See Figure 6-6.)
by lighting the lamp and disabling the
Latch output QA of U2 goes high which
enables the REPRO Light Indicator, Re-
PLAY switch line. C10 is still charged
produce Enable, Carriage Solenoid,
and is the last logic level U2 sees on
Capstan Enable and Take-Up motor. (The
its input lines. RECORD then being the
take-up motor drive receives partial
last command, resets play, latches out
activation due to the Zener action of
the PLAY mode, inhibits REPRO and en-
VR-1). The spool brakes are disabled
ables the Record Enable Line. All the
by the high output of QA. The carriage
functions for RECORD are the same as
assembly and capstan pinch rollers are
PLAY (except for Reproduce Enable) and
slower to engage than the take-up
are enabled by the QB output of U2.
spool motor action, and tape would slip
CR14 prevents voltage at the RECORD
switch from appearing at SA input. CR8
by the head without some hold back
prevents voltage from the base of Q1
tension. C3 and C4 provide a wide
reaching the RECORD switch and causing
pulse of energy to the supply spool
the accidental enabling of RECORD. CR2
prevents any positive base voltage on
Q1.
6-8
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