Aiwa CX-LZX7 Service Manual page 44

< TUNER SECTION > <HR>
1. Clock Frequency Check
Settings : • Test point : TP2(CLK)
Method : Set to AM 1602kHz and check that the test point is
2052kHz ± 45Hz.
2. AM VT Check
Settings : • Test point : TP1(VT)
Method : Set to AM 1602kHz and check that the test point is less
than 8.0V. Then set to AM 531kHz and check that the
test point is more than 0.6V.
3. AM Tracking Adjustment
Settings : • Test point : TP8(Lch), TP9(Rch)
• Adjustment location : L981(1/3)
Method : Set to AM 999kHz and adjust L981(1/3) so that the
test point becomes maximum.
4. AM IF Adjustment
Settings : • Test point : TP8(Lch), TP9(Rch)
• Adjustment location :
L772 ............................................................ 450kHz.
5. FM VT Check
Settings : • Test point : TP1(VT)
Method : Set to FM 108.0MHz and check that the test point
is less than 8.0V. Then set to FM 87.5MHz and check
that the test point is more than 0.5V.
6. FM Tracking Check
Settings : • Test point : TP8(Lch), TP9(Rch)
Method : Set to FM 98.0MHz and check that the test point is less
than 9dBµV.
7. DC Balance / Mono Distortion Adjustment
Settings : • Test point : TP3, TP4 (DC Balance)
• Adjustment location : L771
• Input level : 60dBµV
Method : Set to FM 98.0MHz and adjust L771 so that the voltage
between TP3 and TP4 becomes 0V ± 0.04V. Then check
that the distortion is less than 1.3%.
8. Output Level Check
<AM>
Settings : • Test point : TP8(Lch), TP9(Rch)
• Input level : 74dBµV
Method : Set to AM 1000kHz and check that the test point is
175mV ± 3dB.
<FM>
Settings : • Test point : TP8(Lch), TP9(Rch)
• Input level : 60dBµV
Method : Set to FM 98.0MHz and check that the test point is
700mV ± 3dB.
9. FM Seperation Check
Settings : • Test point : TP8(Lch), TP9(Rch)
• Input level : 60dBµV
Method : Set to FM 98.0MHz and check that the test point is
more than 25dB.
– 42 –
TP8(Lch), TP9(Rch) (Distortion)