Adjustment Procedures; Cassette Deck Section - Panasonic SA-AK640GCP Service Manual

13 Adjustment Procedures

13.1. Cassette Deck Section

· Measurement Condition
− − − − Reverse-mode selector switch:
− − − − Deck Tape Select: NORMAL
− − − − 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. Insert the test tape (QZZCWAT) to DECK 2 and playback
(FWD side) the middle portion of it.
2. Adjust Motor VR (DECK 2) for the output value shown
below.
Adjustment target: 2910 ~ 3090 Hz (NORMAL speed)
3. 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.
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 as below.
13.1.3.1. Cassette Deck Section
Below is the locations of test points for Deck P.C.B.:-
Fig. 1
Standard Value: 89 ~ 110 kHz
13.1.2. Bias 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
standard value.
Bias voltage for Deck 2
Fig. 4
43
SA-AK640GCP
14±4mV (Normal)
Fig. 2
Fig. 3