Sony WRT-847A, Service Manual

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3-2 WRT-847A/847B
3-2. Adjustments
This section describes the following adjustments and checks
required to satisfy specifications.
Adjustment and Check Items
3-2-1. Power Supply Voltage Check
3-2-2. Carrier Frequency Adjustment
3-2-3. RF Power Output Adjustment
3-2-4. Reference Frequency Deviation Adjustment
3-2-5. Maximum Frequency Deviation Adjustment
3-2-6. Distortion Ratio Check
3-2-7. S/N Check
3-2-8. Frequency Characteristics Check
3-2-9. Tone Signal Adjustment
3-2-10. Battery Alarm Signal Check
3-2-11. Spurious Emissions Check
3-2-12. Occupied Band width Check
Preparation
1. Remove the MB-914 board, DP-341 board, RF-96 board
and CN-2055 board from WRT-847A/847B unit, and
then the MB-914, DP-341, RF-96 boards must be con-
nected electrically as shown below.
Refer to the “Section 2. Service Overview” for removal.
2. Connect the RF adjusting cable (J-6402-390-A) with RF
conversion connector (J-6402-490-A) to the antenna
connector (CN402) on the RF-96 board as shown below.
3. Connecting the DC power supply
Supply the DC power to the battery terminals on the
MB-914 board as shown below.
Check
After the DC power supply connection is completed, set
the power switch (S301) to ON, and check the level on
DC ammeter.
DC ammeter indication level: 140 to 200 mA
RF adjusting cable
RF conversion
connector
CN402
CN201
CN401
CN303
CN302
(B side)
RF-96 board
DP-341 board
MB-914 board (A side)
+
–
+
–
DC ammeter
Solder Solder
DC power supply
3.0 ± 0.1 Vdc
GND VCC
MB-914 board (A side)
CN402