Revox C115 User Manual

REVOXx’°
C115
E
13
3.
FUNCTIONAL
DESCRIPTION
FRONT
UNIT:
The
front
unit
contains
the
input keypad
as
well
as
the
microprocessor.
The
latter
is
responsible
for
scanning the
3.1
Cassette
deck
keyboard,
for
controlling
the
display,
and
for
calculating
The cassette deck is equipped with a dual capstan drive.
The controlled DC motor drives the righthand capstan
shaft via a flat belt. From this shaft the left-hand capstan
is driven by a second flat belt.
The capstan drive control is integrated in the motor hous-
ing. The capstan speed can be adjusted with a trimmer (-
-> 4.2.3).
The headblock assembly is actuated by the capstan mo-
tor via a cam disc. Coupling/decoupling is performed by a
small solenoid.
The brakes are also controlled via a cam disc.
The spooling motor drives the spindles via a gear train.
The left-hand or right-hand spindle is driven, depending
on the selected spooling direction. Each spindle has its
own light barrier that supplies the tape timer information
to the microprocessor.
3.2 Control
POWER SUPPLY:
The power supply Unit contains the power supply and the
spooling motor drive.
The power supply generates the following voltages:
- +/-12 V DC for audio, stabilized a with rectifier (D 4 -
11) and voltage regulator (IC 1 and 2)
- +14 V DC unstabilized from the rectifier (D 12 - 19),
for the capstan motor, the spooling motor and the so-
lenoid.
'»~ 45 VDC from the +14 V, stabilized by IC 3, for the
processor control.
- 4,3 V AC (FIL) for the heating coil of the display
- -30V DC from D 20 for the display.
if the 5 V supply drops below a certain value when the
cassette recorder is switched off or in the event of a
power failure, a reset is generated by the regulator IC 3.
IC 4 contains the drivers for the spooling motor. Depend-
ing on the cassette deck status, a corresponding voltage
is applied to the spooling motor.
the tape timer and peak meter information.
A special feature of this processor are the high-voltage
outputs through which the FIP can be controlled directly.
The internal A/D converter is used for peak level meas-
urement and for keyboard scanning.
3.3 Audio electronics
AUDIO BOARD
The complete audio electronics is located on the audio
board.
Recording section:
The input signal is taken via the volume control RV 01 to
the Dolby B/C encoder Q 651. The multiplex filter is con-
nected after the first linear state and switched on or off
by means of the transistors Q 653 and Q 654. After a
second stage within Q 651, the audio signal is taken to
the monitor switch QT 51 (changeover between source
and tape). The coded record signal is available on pins
21 and 22 of Q 651 and is taken via internal and external
calibration potentiometers to the record amplifier QK 01.
The latter is equipped with internal equalization selection
switches. After the RF bias trap the RF is added to the
AF signal via the transformers L 901 and L 902. The HX
PRO circuit is implemented with IC Q 901 which contains
the rectifier, the integral controller and the VCA. IC Q 921
is used for switching the HX PRO circuit on / off which in
this recorder is continually on. This means that the HX
PRO circuit always receives the signal after the two
lowpass elements R 906 / C 902 and R 905/901. The
erase oscillator is implemented as a push-pull stage and
oscillates with a frequency of 105 kHz. It supplies the RF
signal to the HX PRO circuit.
Reproduce section:
The reproduce signal is amplified in IC QJ 31 which fea-
tures a low-noise FET input stage. The reproduce time
constants are implemented in a push-pull stage and can
be changed over between 70 and 120 us (QU 05 / 06).
The output signal is taken to the level and treble control
as well as to the Dolby B/C Decoder chip Q 601. The ag-
gregate signal of the right-hand and left-hand channel is
taken to the pause detection circuit implemented with QB
01. The output of the Dolby detector is taken to the moni-
tor switch and to the peak meter amplifier QX 01, to the
headphones volume control comprising the amplifier
stage QG 01, and to the buffer amplifier IC 1 /1C 2 (on
the IN/OUT unit).

Revox C115 Specifications

General

Brand	Revox
Model	C115
Category	Tape Deck
Language	English