Cobra MR HH475 FLT BT/EU, Service Manual

Page: 10 / 67

ADJUSTMENT PROCEDURE
Step Adjustment Test Point Procedure
1 L18 Receive
*1
TP1
1. Connect digital voltmeter to TP1 on RF PCB.
2. Set CH01 .
3. Adjust L18.
4. TP1 voltage 1.2~1.6V DC.
2 L20 Transmit
*1
TP1
1. Connect a digital voltmeter to TP1 on RF PCB.
2. Set CH01 .
3. Adjust L20.
4. TP1 voltage 1.2~1.6V DC.
3 VC1
*2
1. Connect the antenna coupler output to a frequency counter.
2. Set channel to CH01 (156.050 MHz).
3. Adjust VC1 to obtain a frequency reading 156.050 MHz
±
200Hz.
4
VR2
Modulation
*2
1. Connect the antenna coupler output to an FM linear detector.
2. Connect Audio Oscillator to Microphone Jack.
3. Set unit to transmit mode.
4. Set audio oscillator output to -23dBm 1 kHz.
5. Adjust VR2 to obtain
±
4.5 kHz deviation.
Remark:
*1: Please reference the “Main PCB Bottom View” drawing in page
13.
*2: Please reference the “Main PCB Top View” drawing in page
12.
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