Tascam 122 - 3. Circuit Description; Control Section Overview; 3-1. System Control IC

122 ~
3. CIRCUIT DESCRIPTION
The following conditions are assumed:
* The deck is initially in the stop mode unless
otherwise specified.
* Voltages, waveforms, and operating times
given in the text are typical ones for reference.
* I n the description of ampl ifiers (sections 3-11
through 3-14), generallly, the left channel is
described.
* In the illustrations, circuit boards, terminals,
and connectors are omitted.
* Part numbers are assigned as follows:
100-199: Muting circuit, bias osciUator cir·
cuit, and L-channel record/repro-
duce circuit mounted on record/
reproduce & control PCB
200-299: R-channel record/reproduce cir·
cuit on record/reproduce & con-
trol PCB
300-399:
L-channel monitor, record, and
HX circuits and common L- and
R-channel circuits mounted on
lever switch PCB
400-499:
R-channel monitor, record, and
HX circuits mounted on lever
switch PCB
500-599:
Power supply PCB circuits.
600-699: System control circuits and
mechanical parts mounted on reo
cord/reproduce & control PCB
and joint PCB
700-799: L-channel meter circuit and phone
amplifier circuit mounted on
meter amplifier PCB
800-899: R-channel meter circuit and phone
amplifier circuit mounted on
meter amplifier PCB
CONTROL SECTION
3-1. SYSTEM CONTROL IC
3-1-1 Pin assignments
Output Control input
Ir ~ ---------- ----------~\ r-\
.8 F. FWO FAST REW PLAY PAUSE
AR
US01
M54410P
(T O P VIEWI
PLAY STOP f . fWO MEMO REW PAUSE REt
GNO
\~ ______ ....JI '--.I , '- ____ ---11
OperOling inpulS Control input Operating inpulS
Fig. 3-1 Pin assignments
Pin No . Pin name Function
1
PLAY
Reproduce start signal input terminal. Signal level: L
2
STOP
Stop signal input term inal Si gnal level : L
Operation
3
F.
FWD
Fast-forward signal input terminal. Signal level : L
inputs
5
REW Rewind signal input terminal.
Signallavel: L
6
PAUSE
Pause signal input terminal.
Signal level : L
7
REC Record signal input terminal.
Signal level: L
Control
4
MEMO Memory input terminal (resets rewind mode when at L level)
inputs
9
AR
Record inhibit signal input terminal (L level: record inhibited, H level: record enab led)
10
REC H-Ievel signal output terminal during record/reproduce or record/pause mode
11
PAUSE
H -level signal output terminal during pause mode
Outputs
12
PLAY H-Ievel signal output terminal during reproduce mode.
power
13 REW H- Ievel signal output terminal during rewind mode .
14 FAST H-Ievel signal output terminal during rewind or fast-forward mode.
15
F.FWD
H-Ievel signal output terminal during fast-forward mode.
Power
8
GND Ground terminal.
16 +B
Power supply terminal (standard: +5 V +/-10%, absolute maximum: +7.0 V)
I
6