Nakamichi 481, Руководство по обслуживанию

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positioned perfectly vertical to the tape surface. Other-
wise, the running tape might become out of the tape
guide resulting in irregular movement.
2.1.4. Mechanism Control Cam Operation
Refer to Fig. 2.1.6 Mechanism Control Cam timing chart.
Function of N-481 Mechanism is done by Cam Control.
Cam is driven by the Control Motor. The Motor operates
so as to result zero in the difference of voltages between
each voltage corresponding to mechanism function and
each reference voltage which corresponds to each com-
mands of the Control Switch. When the difference comes
to zero, then it stops. In this way, each function is kept
properly operated. For further details, please see the ex-
planation on Logic Control. Here we explain principle of
its mechanical functions.
Cam Control System works as follows: Cam Drive Gear is
driven by Control Motor by means of Drive Belt. Cam
Drive Gear is related to the cam with which each function
may be mechanically set on.
(1) Play Mode
Press the Play Switch to make it Play mode. Then the
Cam begins to move from Stop position to Play position
and the Play mode will be set.
The Head Base which is linked to the Cam and which is
normally pushed against the Stop position gets released
and the Head Base will slowly come out for playing. To
explain this function, first the Head Base is latched and
the Reel Motor begins to turn. Then the Pressure Roller
will be pushed and the Brake will be released. Now the
tape begins to run. If you press the Pause Switch at this
stage, it comes to Pause mode. Brake operates and the
Pressure Roller moves away from the Capstan and the
Reel Motor stops.
Play mode may be changed to Stop mode by pressing the
Stop Switch, and latch of the Head Base being released.
The Cassette Case cannot be opened because of the
latched eject effect unless it is in Stop mode.
(2) Record Mode
By pressing the Record Switch and the Pause or Play
Switch, it may be made to Record mode. The Cam at this
moment moves from Stop position to Rec. position. At the
same time, Rec. Trigger Mechanism is driven and the
Record Switch on the Main P.C.B. is switched on to the
Record side. Further, the Cam turns until it comes to the
Pause or Play position. On the other hand, the Rec. Trig-
ger Mechanism is released during this process. When the
Cam is set in Rec./Pause or Rec./Play position, Record
signals will be sent to Bias Oscillating Circuit from Logic
Control Circuit to let the Bias to oscillate.
Press the Stop Switch and the Cam comes back to the
Stop position. At the same time, it will set the Record
Switch on the Main P.C.B. to the Play side.