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MK-100
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However, as mentioned above, since X12 continues to be turned on and off alternately during rotation of the take-up disc,
C37 is immediately discharged through R53 and X12.
When the tape reaches to its end and the take-up disc stops rotating, X12 is already turned off and the voltage between C37
terminals gradually increases. Then, when the voltage sufficiently increases to about 2.7V, X13 is biased and turned on
through the zener diode D14. As a result, X13 earthes X14's a base and X14 is no longer biased but turned off, thereby halt-
ing the motor. At this time, the collector voltage at X14 increases to correspond to the power supply voltage, switching on
the oscillator circuit and producing the warning tone from the speaker.
Motor
Warning Tone
OSC. Circuit
Fig. 20
The
recording
signal from
the main
amplifier, during recording,
is converted
into direct current through
R42 and the
quadrupled voltage rectifier circuit composed of C32 — C35 and D10 — D13.
Then
the direct current, proportional to this signal, flows through the attenuator composed of R45 — R49 and applied to
transistors X8 — X10, resulting in the lighting of the LEDs according to their specific lighting levels.
In the cases of modes other than stop or recording, a voltage in proportion to the power supply voltage produced through
R41 and R37 is applied to X9 through D8. When the power supply voltage is more than 4.2V (+0.2V), X9 is turned on and
the LED of N (D17) lights.
°
Recording Signai
|
0 from Main Amp.
—
R4l
Dil2
+B
No. 0002
—~10—
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