Sony WRT-807B, Service Manual

Page: 24 / 64

3-8
WRT-807B (U/CE)
3-2-7. S/N Check
Equipment and Tools
DC power supply
DC output voltage : + 1.5
±
0.1 Vdc
DC ammeter
Audio analyzer
Modulation analyzer
SMA-BNC (J) connector (Part No. J-6402-490-A)
RF conversion connector (Part No. J-6402-400-A)
AF input cable (See “How to make a AF input cable” on
page 3-1.)
Connections
Same as “3-2-6. Distortion Ratio Check”.
Switch and Control Setting
Same as “Switch and Control Initial Setting” on page 3-3.
Procedure
(1) Connect the audio analyzer (level meter) to the AF OUT
connector on the modulation analyzer.
(2) Connect the modulation analyzer to the antenna connec-
tor (CN305) with SMA-BNC (J) connector (and RF
conversion connector).
Set the modulation analyzer as below;
MEASUREMENT
: FM
MEASUREMENT RANGE :
±
40 kHz (manual)
HPF : 50 Hz
LPF : 15 kHz for HEWLETT
PACKARD equipment
20 kHz for ANRITSU
equipment
DE EMPHASIS : 50 u s
(3) Input 1 kHz,
_
55 dBV (
_
52.8 dBm) signal to the AF
input connector (CN303/CN-1868 board) with AF input
cable from audio analyzer (oscillator).
(4) Set the audio analyzer to S/N measurement (with A-
weighted filter) .
(5) Check that the S/N reading is more than 32dB. (with AF
input connector (CN303/CN-1868 board) short-circuit-
ed).
3-2-8. Frequency Characteristics Check
Equipment and Tools
DC power supply
DC output voltage : + 1.5
±
0.1 Vdc
DC ammeter
Audio analyzer
Modulation analyzer
Oscilloscope
SMA-BNC (J) connector (Part No. J-6402-490-A)
RF conversion connector (Part No. J-6402-400-A)
AF input cable (See “ How to make a AF input cable” on
page 3-1.)
Connections
Same as “3-2-6. Distortion Ratio Check”.
Switch and Control Setting
Same as “Switch and Control Initial Setting” on page 3-3.
Procedure
(1) Connect the audio analyzer to the AF OUT connector
on the modulation analyzer.
(2) Connect the modulation analyzer to the antenna connec-
tor (CN305) with SMA-BNC (J) connector (and RF
conversion connector).
Set the modulation analyzer as below;
MEASUREMENT
: FM
MEASUREMENT RANGE :
±
40 kHz (manual)
HPF : 50 Hz
LPF : 15 kHz or 20 kHz
DE EMPHASIS : 50
u
s
(3) Set the audio analyzer to level meter mode.
(4) Input 1 kHz,
_
55 dBV (
_
52.8 dBm) signal to the AF
input connector (CN303/CN-1868 board) with AF input
cable from audio analyzer (oscillator).