JVC CA-MXKA7, Service Manual

Page: 18 / 67

MX-KA7
1-18
Adjustment method
Measurement instruments required
for adjustment
1. Low frequency oscillator.
This oscillator should have a capacity to output
0dB to 600ohm at an oscillation frequency of
50Hz-20kHz.
2. Attenuator impedance : 600ohm
3. Electronic voltmeter
4. Frequency counter
5. Wow flutter meter
6. Test tape
VT712 : For Tape speed and wow flutter ( 3kHz)
VT703 : For Head angle (10kHz)
7. Blank tape
TAPE
I
: AC-225 TAPE
II
: AC-514
8. Torque gauge : For play and back tension forward;
TW2111A, Reverse; TW2121A Fast Forward and
Rewind; TW2231A
9. Test disc: CTS-1000(12cm),GRG-1211(8cm)
10. Jitter meter
Measurement conditions
Power supply voltage
AC 120V (60Hz)
Measurement
output terminal : Speaker out
: TP101(Measuring for TUNER/
DECK/CD)
: Dummy load 6ohm
Radio input signal
AM modulation frequency : 400Hz
Modulation factor : 30%
FM modulation frequency : 1kHz
Frequency displacement : 22.5kHz
Frequency Range
AM 530kHz~1710kHz
FM 87.5MHz~108MHz
Standard measurement positions of
volume and switch
Power : Standby (Light STANDBY Indicator)
Sound Turbo, A, BASS EX : OFF
Sound mode : OFF
Main VOL. : 0 Minimum
Travers mecha set position : Disc 1
Precautions for measurement
1. Apply 30pF and 33kohm to the IF sweeper output
side and 0.082 F and 100kohm in series to the
sweeper input side.
2. The IF sweeper output level should be made as
low as possible within the adjustable range.
3. Since the IF sweeper is a fixed device, there is no
need to adjust this sweeper.
4. Since a ceramic oscillator is used, there is no need
to perform any MPX adjustment.
5. Since a fixed coil is used, there is no need to adjust
the FM tracking.
6. The input and output earth systems are separated.
In case of simultaneously measuring the voltage in
both of the input and output systems with an
electronic voltmeter for two channels, therefore, the
earth should be connected particularly.
7. In the case of BTL connection amplifier, the minus
terminal of speaker is not for earthing. Therefore,
be sure not to connect any other earth terminal to
this terminal. This system is of an OTL system.