Panasonic SA-AK631, Service Manual

Page: 49 / 112

13.1. Cassette Deck Section
· Measurement Condition
− − − −
Make sure head, capstan and press roller are clean.
− − − − Judgeable room temperature 20 ± 5 °C (68 ± 9°F)
· Measuring instrument
− − − − EVM (DC Electronic voltmeter)
−
− −
−
Digital frequency counter
· Test Tape
− − − − Tape speed gain adjustment (3 kHz, -10 dB);
QZZCWAT
13.1.1. Tape Speed Adjustment (Deck 1/2)
1. Set the tape edit button to “NORMAL” position.
2. Insert the test tape (QZZCWAT) to DECK 2 and playback
(FWD side) the middle portion of it.
3. Adjust Motor VR (DECK 2) for the output value shown
below.
Adjustment target: 2940 ~ 3060 Hz (NORMAL speed)
4. After alignment, assure that the output frequency of the
DECK 1 FWD are within ±60 Hz of the value of the output
frequency of DECK 2 FWD.
Fig.1
13.1.2. Bias and Erase Voltage Check
1. Set the unit “AUX” position.
2. Insert the Normal blank tape (QZZCRA) into DECK 2 and
the unit to “REC” mode (use “ l REC/STOP” key).
3. Measure and make sure that the output is within the
1. Connect the instrument as shown in Fig.5.
2. Set the unit to AM mode.
3. Apply signal as shown in Fig. 5 from AM-SG.
4. Adjust Z2602 so that the output frequency is maximized in
Fig. 6.
standard value.
Bias voltage for Deck 2 14±4mV (Normal)
Erase voltage for Deck 2 80mV (Normal)
Fig.2
Fig.3
13.1.3. Bias Frequency Adjustment (Deck
1/2)
1. Set the unit to “AUX” position.
2. Insert the Normal blank tape (QZZCRA) into DECK 2 and
set the unit to “REC” mode (
l
use “REC/STOP” key).
3. Adjust L1002 so that the output frequency is within the
standard value.
Standard Value: 97 ±8 kHz
Fig.4
Fig.5
13 Measurements and Adjustments
13.2. Tuner Section
13.2.1. AM-IF Alignment
49
SA-AK631PL