Adjustments - Yamaha TX-497 Service Manual

TX-497
TEST POINTS
<FM TUNER SECTION>
Step Adjustment item
Rough adjustment of
discriminator balance.
1
Rough adjustment of
2
monaural distortion.
Fine adjustment of
3
discriminator balance.
Fine adjustment of
4
monaural distortion.
Verification of
5
discriminator balance.
Adjustment of frontend
IFT.
6
Adjustment of stereo
distortion.
7
8
DISCRIMINATOR
BALANCE
LINE OUT
MONAURAL
L R
DISTORTION
TP1
L8
L10
L13 L12 VR4
J6
R51
J7
SEPARATION
VR3
SIGNAL
METER
Signal (ANT IN)
FM SG:
98.1 MHz 70 dBµ
Modulation : 100 %
Monaural : 1 kHz
Same as Step 1.
Same as Step 1.
Same as Step 1.
Same as Step 1.
FM SG:
98.1 MHz 30 dBµ
Modulation : 100 %
Monaural : 1 kHz
FM SG:
98.1 MHz 70 dBµ
Modulation : 100 %
Stereo L or R : 1 kHz
AM ANT GND FM ANT
PK2
STEREO
DISTORTION
TP2
VR2
L5
VR1
AM SENSITIVITY
GND
TP3
J73 J108
Reception Adjusted
frequency point
Preset L8
A-4: 98.1 MHz (right side)
Same as Step 1. L8
(left side)
Same as Step 1. L8
(right side)
Same as Step 1. L8
(left side)
Same as Step 1.
Same as Step 1. Frontend
IFT
Same as Step 1. VR1, VR2
PK1
FRONTEND
IFT
Test point
Rating
DC 0 V ±100mV
TP1, TP2
(both end
at tuning point.
of R51)
OUTPUT
Minimize distortion.
DC 0 V ±50mV
TP1, TP2
OUTPUT
Minimize distortion.
(to less than 0.7%)
DC 0 V ±50mV
TP1, TP2
TP3, GND
Adjust so that the
DC voltage is
maximum.
CAUTION:
If IFT core is turned
excessively, the
sensitivity reduces.
(Maximum ±90°)
OUTPUT Minimize distortion.
Tuning mode is
AUTO.