Akai AP-M7

VIL. ELECTRICAL ADJUSTMENT
7-1. ARM SENSOR VOLTAGE ADJUSTMENT (Refer to Fig. 7-1)
1) Take off the Dust Cover from the Chassis Upper Assy
by loosening the five screws.
2) Connect a digital voltmeter between the point @
and ground. Move the Tone Arm by hand in the
direction as shown in Fig. 7-1 to move the Tone Arm
Shutter out of the photocoupler, and adjust VR1 on
7-2, SPEED ADJUSTMENT (Refer to Fig. 7-2)
FRONT
INSULATOR
y
BOTTOM COVER
@=— vRI(33-1/3rpm)
t!)
@=— vr2(45rpm)
0000 oo000 oo 0 0
Fig. 7-2 Bottom View
SERVICE MANUAL AP-M7/S.
TONE ARM
TONE ARM SHUTTER
PHOTO COUPLER (PH |)
Fig. 7-1 Inside View of Moving Base Block
MOVING BASE P.C Board so that the voltmeter
reads 4.1V 0.1V.
3) After the adjustment in item 2) is completed, move
the Tone Arm back to the original position and
confirm that the voltage at the point ® is more than
1.8V. If the voltage is less than 1.8V, re-adjust VR1
so that the voltage is 2.0V + 0.1V.
1) Using Test Records
1. Play a Test Record (33-1/3 rpm, 1,000 Hz)
2. Set the Speed Selector to 33-1/3 rpm.
3. Adjust VR1 (3K) so that the speed is 1,000 Hz +
5 Hz.
4. Set the Speed Selector to 45 rpm.
5. Play a Test Record (45 rpm, 1,000 Hz)
6. Adjust VR4 (20K) so that the speed is 1,000 Hz +
5 Hz.
2) Using a stroboplate
1. Set the Speed Selector to 33-1/3 rpm.
2. Adjust VR1 (3K) so that the strobe (33-1/3 rpm,
50 or 60 Hz) stays still.
3. Set the Speed Selector to 45 rpm.
4. Adjust VR2 (20K) so that the strobe (45 rpm 50
or 60 Hz) stays still.
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