Adjustment - JVC MX-GA9V Service Manual

4.1 Measurement instruments required for adjustment
(1) Low frequency oscillator,
This oscillator should have a capacity to output 0dBs to
600Ω at an oscillation frequency of 50Hz-20kHz.
(2) Attenuator impedance : 600Ω
(3) Electronic voltmeter
(4) Frequency counter
(5) Wow flutter meter
(6) Test tape
VT712 : For Tape speed and wow flutter ( 3kHz)
VT710 : Head azimuth
VT724 : For Reference level (1kHz)
(7) Blank tape
TAPE : AC-225
(8) Torque gauge : For play and back tension
Forward ; TW2111A, Reverse ; TW2121A
Fast Forward and Rewind ; TW2231A
(9) Test disc
Disc : CTS-1000(12cm), GRG-1211(8cm)
(10) Jitter meter
4.2 Measurement conditions
Power supply voltage
AC110V/127V/220V/230V~240V~, adjustable
Measurement output terminal
• Speaker out
• TP101(Mesuring for TUNER/DECK/CD)
• Dummy load 6Ω
1-36 (No.MB011)
SECTION 4

ADJUSTMENT

4.2.1 Radio input signal
AM modulation frequency : 400Hz
Modulation factor : 30%
FM modulation frequency : 400Hz
Frequency displacement : 22.5kHz
4.2.2 Frequency Range
AM : 531kHz~1710kHz
FM : 87.5MHz~108MHz
4.2.3 Standard measurement positions of volume and switch
Power : Standby (Light STANDBY Indicator)
Sub woofer VOL. : Minimum
Sound mode : OFF
Main VOL. : 0 Minimum
Traverse mecha set position : Disc 1
Mic MIX VOL : MAX
ECHO : OFF
4.2.4 Precautions for measurement
(1) Apply 30pF and 33kΩ to the IF sweeper output side and
0.082 F and 100kΩ in series to the sweeper input side.
(2) The IF sweeper output level should be made as low as pos-
sible 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 per-
form 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 con-
nect any other earth terminal to this terminal. This system
is of an OTL system.