Nakamichi 481 Service Manual - page 18
2.3.8. Reel Motor Governor
Refer to Fig. 2.3.12 circuit diagram.
One end of the reel motor is connected with +12 V and the other end is a terminal for
controlling.
During FF mode, Q413 is turned ON and the reel motor is grounded. Accordingly, the reel
motor turns in the direction of fast-forwarding. On the other hand, during REW mode, +24 V
(REW H) is applied to the reel motor and the reel motor turns in the direction of rewinding.
During PLAY (PLAYBACK or RECORD) mode, Q412 is turned OFF and the Pause-position
signal becomes H, as a result,
Q417 is turned OFF and the reel motor is turned at a constantt
speed by the governor composed of Q414 and Q415.
During PLAY/PAUSE mode, Q412 is turned ON and the Pause-position signal becomes L,
therefore, Q417 is turned ON, Q414 is biased in the reverse direction, and Q414 is cut off, thus
the reel motor does not turn.
Take-up function at loading:
When a cassette tape is inserted and loaded, Eject Switch will become open. Consequently,
the base current is applied to Q413 through C409, and Q413 is turned ON pulse-likely. During
Q413 is turned ON, the reel motor turns
in
the direction of fast-forwarding and eliminates tape
loosening of the cassette tape if any.