Control Circuit - Pioneer RT-707 Service Manual

6. CIRCUIT DESCRIPTIONS
The block diagram is shown on page 7.
Model RT-707 is an open reel tape deck charac-
terized by direct drive 4-track 2-channel configu-
ration, 3 motors, 4 heads autoreverse
The sensor touch pushbuttons used in most 3-
motor tape decks necessitate a relatively large num-
ber Of relays in the transport control electronics;
the RT-707, however, uses locking type pushbut-
tons which permit simplified circuit construction
and also facilitate automatic unattended recording
in conjunction with a timer.
6.1 POWER SUPPLY
When the power switch S, is switched on, AC100V
is supplied to the capstan motor from the secon-
dary side of the power transformer, and the motor
begins to rotate. A DC voltage rectified in Dgo,
D4o2, stabilized in the stabilizer formed by Q4o1,
Q4o2 and ZD4o,, is supplied to the control circuit
(Fig. 1).
6.2 CONTROL CIRCUIT
The control circuit is shown in Fig. 2. Table 1
indicates the transistor states for the different
transport modes.
@ Play Function (Fig. 2)
Si
|
ACI20V -~ ?
60Hz
;
a
Ry6o1-2 ~ a
10
Fig. 1