S/N Check; Frequency Characteristics Check - Sony WRT-800A Service Manual

3-2-6. S/N Check

Equipment and Tools
Same as "3-2-5. Distortion Ratio Check" expect the
following setting.
Modulation analyzer
MEASUREMENT RANGE : ± 10 kHz
Switch and control setting
S301, S302, S303, S304/ RF-87 board (A-side)
WRT-800A S301
AU66 model _
Connections
Same as "3-2-5. Distortion Ratio Check".
Procedure
(1) Connect the audio analyzer (level meter) to the AF
OUT connector for the modulation analyzer.
(2) Input 1kHz, _43.5 dBV (_41.3 dBm) signal to the
CN101/AU-258 board from audio analyzer (oscillator)
with AF input connector.
n 0 dBV=1 Vrms, 0 dBm=0.775 Vrms
(3) Set the audio analyzer to S/N measurement mode (with
A-weight filter ON).
(4) Check that the S/N reading is more than 32 dB.
3-7
S302 S303 S304 Channel
setting
0 1 OFF 67-01

3-2-7. Frequency Characteristics Check

Equipment and Tools
Same as "3-2-5. Distortion Ratio Check" expect the
following setting.
Modulation analyzer
MEASUREMENT RANGE : ± 40 kHz
Switch and control setting
S301, S302, S303, S304/ RF-87 board (A-side)
WRT-800A S301
AU66 model _
Connections
Same as "3-2-5. Distortion Ratio Check".
Procedure
(1) Connect the audio analyzer (level meter) to the AF
OUT connector for the modulation analyzer.
(2) Set the audio analyzer to level meter mode.
(3) Input the 1 kHz, _43.5 dBV (_41.3 dBm) signal to the
CN101/AU-258 board from audio analyzer
(oscillator).
(4) Reads the indication on the audio analyzer (level
meter).
(5) Set the SENSITIVITY on the audio analyzer (level
meter) so that the audio analyzer (level meter) reads
0 dB.
(6) Switch the oscillation frequency for the audio analyzer
(oscillator) from 1 kHz to 100 Hz.
(7) Check that audio analyzer (level meter) reading is
0± 1.0 dB.
(8) Next, switch the oscillation frequency for the audio
analyzer (oscillator) from 100 Hz to 10 kHz.
(9) Check that the reading for the audio analyzer (level
meter) is _1.0± 1.0 dB.
S302 S303 S304 Channel
setting
0 1 OFF 67-01
WRT-800A (AU)