JVC CA-UXP55, Service Manual

Page: 19 / 42

(No.22036)1-19
SECTION 3
Adjustment
3.1 Adjustment method
Tuner section
FM tuning range: 87.5MHz~108.00MHz
AM tuning range: 522kHz~1,629kHz
Voltage applied to tuner +B : DC5.7V
VT : DC 12V
Reference measurement
output 26.1mV(0.28V)/3
Input positions AM : Standard loop antenna
FM : TP1 (hot) and TP2 (GND)
Standard measurement position of volume
Function switch to Tape
Beat cut switch to Cut
Super Bass/Active hyper Bass to OFF
Bass Treble to Center
Adjustment of main volume to reference output
VOL : 28
Precautions for measurement
1. Apply 30pF and 33k to the IF sweeper output
side and 0.082 F and 100k 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 MIX 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 carefully.
7. In the case of BTL connection amp., 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 BTL system.
8. For connecting a dummy resistor when measuring
the output, use the wire with a greater code size.
9. Whenever any mixed tape is used, use the band
pass filter (DV-12).
Measurement conditions
Power supply voltage
AC 230V ~ , 50Hz
Reference output : Speaker : 0.775V/4
: Headphone : 0.077V/32
Reference frequency and
input level ------------------------------ 1kHz, AUX : -8dBs
Measurement output terminal ------- at Speaker J3002
Load resistance --------------------------- 4
Radio Input signal
AM frequency --------------------------------------- 400Hz
AM modulation ---------------------------------------- 30%
FM frequency --------------------------------------- 400Hz
FM frequency deviation ------------------------ 22.5kHz
Measurement Instruments Required for
Adjustment
1. Low frequency oscillator
This oscillator should have a capacity to output
0dBs to 600 at an oscillation frequency of
50Hz-20kHz.
2. Attenuator impedance : 600
3. Electronic voltmeter
4. Distortion meter
5. Frequency counter
6. Wow & flutter meter
7. Test tape
VT703L : Head azimuth
VT712 : Tape speed and running unevenness
(3kHz)
VT724 : Reference level (1kHz)
8. Blank tape
TYPE : AC-225
TYPE : AC-514
9. Torque gauge : For play and back tension
FWD(TW2111A), REV(TW2121a) and
FF/REW(TW2231A)
10. Test disc: CTS-1000