Measurements And Adjustments; Cassette Deck Section; Tape Speed Adjustment (Deck 1/2); Bias And Erase Voltage Check - Panasonic SC-TM23 Service Manual

14.1 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

14.1.1 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.

14.1.2 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 "• REC/STOP" key).
3. Measure and make sure that the output is within
the standard value.
Bias voltage for Deck 2
Erase voltage for Deck 2

14 Measurements and Adjustments

Fig.1
14±4mV (Normal)
80mV (Normal)
Fig.2

14.1.3 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 (• use "REC/STOP"
key).
3. Adjust L1002 so that the output frequency is
within the standard value.

14.2 Tuner Section

14.2.1 AM-IF Alignment

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.
42
Fig.3
Standard Value: 97 ±8 kHz
Fig.4