Measurement And Adjustment - Panasonic SA-PM30MD Service Manual

10 Measurement and Adjustment

10.1. Cassette Deck Section
Measurement condition
• Record timer : OFF
• Make sure head, capstan and pressure roller are clean.
• Judgeable room temperature 20 ± 5 °C (68 ± 9 °F)
Measuring instrument
• EVM (Electronic Voltmeter)
• Digital frequency counter
10.1.1. Head Azimuth Adjustment
Note :
If you wish to readjust the head azimuth, be sure to adjust with
adhering the casette tape closely to the mechanism by pushing
the cebter of cassette tape with your finger. (Shown in Fig. 1)
1. Connect the measuring instrument as shown in Fig. 2.
2. Replace azimuth screws for both forward and reverse
direction after removing the screw-locking bond left on the
head base.
(Supply part No. of azimath adjusting screw: RHD17015)
3. Playback the azimuth adjustment portion(8kHz, -20dB) of
test tape(QZZCFM). Adjust the azimuth adjusting screw
until the outputs of the L/Rch are maximized. (Refer to Fig.
3)
Make sure that the difference in the peak level between the
left and right channels does not exceed 0.5dB.
4. Perform the same adjustment in reverse playback mode.
Check of the level difference forward and reverse
directions
5. Playback the playback gain adjustment portion(315Hz,
0dB) of test tape(QZZCFM). Check if level difference
between forward and reverse direction is within 1.5dB.
6. After the adjustment, apply screwlock to the azimuth
adjusting screw.
10.1.2. Tape Speed Adjustment
Normal speed (Standard value : 3000 ± 90Hz)
1. Connect the measuring instrument as shown in Fig. 4.
2. Playback the middle portion of the test tape (QZZCWAT).
3. Adjust motor VR for the output value shown below. (Refer
to Fig. 5)
Adjustment target : 3000 ± 40Hz
Fig. 4
Test tape
• Headazimuth adjustment (8 kHz, -20 dB); QZZCFM
• Tape speed adjustment (3 kHz, -10 dB); QZZCWAT
• Playback gain adjustment (315 Hz, 0 dB); QZZCFM
• Normal reference blank tape; QZZCRA
• CrO2 blank tape; QZZCRX
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Fig. 1
Fig. 2
Fig. 3
Fig. 5
SA-PM30MD