Lyrec TR532 Series, Manual

Page: 87 / 195

When the STOP button is pressed, relay 7 will send +24 V to point 14
and then through point 44-A to transistor latch 1 and 2. This will
activate transistor 3 which gives collector voltage to transistors 4
and 5 and drive to transistors 6 and 7 which are outputs for the zero
switch drivers on zeros witch print (placed behind the electrolytic
capacitors). The zero switch for the supply motor is energized by
transistor 7 and the take-up motor by transistor 6. Both situations
keep the mechanical motor brakes free while dynamic braking is going
on (+24 V at point 18).
As long as the tape moves forward point D will be at 0.2 V instead of
approx 12 V. When the STOP button is pressed transistors 4 and 5 get
collector voltage but point D will keep transistor 5 cut off.
Therefore only transistor 7 functions and connects the mains to the
SUPPLY motor.
As long as the tape moves backwards point C will be 0.2 V instead of
approx 12 V. When the STOP button is pressed transistors 4 and 5 get
collector voltage but point C will keep transistor 4 cut off. Only
transistor 6 will switch on and connect the mains to the TAKE-UP
motor.
When the tape stops, or is moving very slowly, point V will drop to
0.2 V from approx 12 V so that relay 5 will be activated. Relay 5
driver transistor will at the same time switch transistor latch 1 and
2 and through this the drive for transistors 3, 4, 5, 6 and 7 is cut
off. The DYNAMIC BRAKE process then comes to an end.
8.8
CAPSTAN AND GUIDE ROLLER SOLENOIDS
When either the START, or START and RECORD buttons are pressed relay 6
is energized. This will c24 V through point 11 and point 3B to
the solenoids. The solenoids return circuit passes through point 4B to
G which connects to 0 V through the diode 1N5404. The pull voltage and
the hold-on voltage for these solenoids are respectively 36 V and 24
V. For approx 1 sec after the START or RECORD buttons have been
pressed -12 V is added at the 0-end of the solenoids by transistors 9
and 10. During the stop mode the 22 µF electrolytic condenser charges
up to 24 V and when start is pressed it will keep transistors 9 and 10
temporarily open and connect -12 V from point E to point G.
1977-05-01 TR532 8.9