SONY WRT-808A
Service Manual

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3-2-12. Battery Alarm Signal Check
Equipment and Tools DC power supply DC output Voltage: +3.0 ± 0.1 V dc DC ammeter Frequency counter Spectrum analyzer Modulation analyzer MM-SMA (J) connector (Part No. J-6402-480-A) SMA-BNC (J) connector (Part No. J-6402-490-A) Switch and Control Setting The following setting is to be perform with the channel select switches (S504 and S505). Transmitting Channel setting: U64 model: 65-01 channel (776.125 MHz) U66 model: 67-01 channel (788.125 MHz) U68 model: 69-01 channel (800.125 MHz) RF power output switch (S401): 50 mW Input LEVEL control (RV101): �_60� (0 dB attenuation) Turn the RV101 clockwise fully.

Procedure n Perform the checking with the MIC input connector (CN101) short-circuited. (1) Set the spectrum analyzer as follow: CENTER FREQUENCY (fc): U64 model: 776.125 MHz U66 model: 788.125 MHz U68 model: 800.125 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: 20 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 ± 0.1 V. (3) While the TP201 is short-circuited to the frame (GND) with a tweezers etc (TONE signal ; OFF), check that level difference between carrier frequency (center frequency level) on spectrum analyzer and tone signal is with in 29 ± 1 dB.
20 dBm

1. Frequency deviation check
Connections (For connecting the DC power supply, refer to the �Preparations� on page 3-2.)
XLR 3Pin (male) - wiring side 2 Short-circuit 3 1

29 ± 1 dB

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

Spectrum analyzer

Tweezers

CN402

MM-SMA (J) connector with SMA-BNC (J) connector

TP201 Frame TP201

Bridge the TP201 and frame (GND) with tweezers.

10

50

Frame

WRT-808A (U)

3-13