Measurements And Adjustments - Panasonic SA-AK66 Service Manual

SA-AK66
12 Measurements and Adjustments
12.1. Cassette Deck Section
+ Measurement Condition
— Tape edit: NORMAL
— Record timer: OFF
— Make sure head, capstan and press roller are clean.
— Judgeable room temperature 20 + 5 °C (68 + 9°F)
+ Measuring instrument
— EVM (Electronic Volmeter)
— Digital quency counter
- Test Tape
— Head azimuth adjustment (8 kHz, -20 dB); QZZCFM
- Tape speed gain adjustment (3 kHz, -10 dB);
QZZCWAT
— Playback gain adjustment (315 Hz, 0 dB); QZZCFM
— CrO2 tape, QZZCRX
12.1.1. 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 is within +60 Hz of the value of the output
frequency of DECK 2 FWD.
UNIT
Digital frequency
counter
12.2. Tuner Section
12.2.1. AM-IF Alignment
- AM-IF ALIGNMENT
12.1.2. 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.
4. Insert the CrO2 tape (QZZCRX).
5. Repeat step 2 and 3.
Bias voltage for Deck 2
Erase voltage for Deck 2
19 + 4mV (Normal)
more than 100mV (Normal)
Bias Erase
1MQ
TP5 O+ UNIT
1KQ
TP4 =
(GND)
12.1.3. 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.
Standard Value: 98 +8 kHz
UNIT
TP12 ¢ TP11 = :
Digital frequency
counter
INDICATOR
(ELECTRONIC
VOLTMETER
OSCILLOSCOPE)
Headphone Jack (32Q)
Fabricate the plug as
shown in Fig. 2 and then
connect the lead wires of
the plug to the
measuring instrument.
ADJUSTMENT(Shown in REMARKS
Fig.3)
SIGNAL GENERATOR OR SWEEP _|RADIO DIAL SETTING
GENERATOR
CONNECTIONS FREQUENCY
Fashion a loop of |450 kHz 30% Mod. |Point of non- Z102 (AM IFT) Adjust for maximum
output. interference (on/about
600 kHz) and radiate signal
into loop of receiver.
20