SONY WRT-822B
Manual de Servicio

Procedure n Perform the checking with the MIC input connector shortcircuited. (1) Set the spectrum analyzer as follow: CENTER FREQUENCY (fc): CE21 model; 470.125 MHz CE33 model; 566.125 MHz CE62 model; 798.125 MHz CE67 model; 838.125 MHz U14 model; 470.125 MHz U30 model; 566.125 MHz U62 model; 758.125 MHz U66 model; 782.125 MHz REFERENCE LEVEL: 20 dBm FREQUENCY SPAN: 200 kHz (20 kHz/DIV) RBW (resolution band width): 3 kHz VBW (video band width): 1 kHz ATT: 30 dB (2) Decrease gradually the DC output voltage of the DC regulated power supply and confirm that the battery alarm signal turns on at 2 ± 0.2 V. (3) Check that level difference between carrier frequency (center frequency level) on spectrum analyzer and tone signal is with in 29 ±2 dB.
20 dBm

2. Frequency check
Connections (For connecting the DC power supply, refer to the �Preparations� on page 3-2.)
MM-SMA (J)connector with SMA-BNC (J) connector Spectrum analyzer

CN301

Jumper wire TP200

MB-940 Board (A side)

TP501 (GND)

Connect a jumper wire between TP200 and TP501 (GND) by soldering. (TONE signal : OFF).

Procedure n Perform the checking with the Mic input connector (SMC94P) short-circuited. (1) Set the modulation analyzer as follows: MEASUREMENT: FM MEASUREMENT RANGE: ± 40 kHz HPF: 4 kHz LPF: >20 kHz DE EMPHASIS: OFF (2) Set the DC output voltage of DC power supply to 1 ± 0.1 V so that battery alarm signal goes on. (3) Check that frequency counter (resolution:0.1 Hz) reading is 32.782 kHz ±1 Hz. (4) After the checking, remove (unsolder) the jumper wire between TP200 and TP501 (GND) on the MB-940 board (A-side).

29 ±2 dB

V : 10 dB/div H : 20kHz/div fc 32.782 kHz

3-12

WRT-822B