Alignment Procedure - Cobra CB 19 DX4 EU Service Manual

Cobra
VCO Voltage
1. Test point TP1 connect to the multi-meter，set UUT enter test mode. Use channel "UP" key to select CH41
(26.565MHz) of DE Band in FM mode.
2. Adjust IFT L17 for 1.0 ± 0.1V on the Multi-meter read， and then checking CH40 (27.99125MHz) of UK Band
should be less than 3.8V.
RX Alignment
Audio Level
1. UUT set to FM mode CH19，output of RF signal generator connect to TP2. Audio dummy load connect to
EXT. Speaker. (@8Ω load)
2. Set RF S.S.G Freq.: 10.695MHz，Mod.: ±1.2KHz，Fmod.: 1KHz, Output level:1mV.
3. Squelch Volume set to minimum position, volume control set to around middle position.
4. Adjust IFT L20 for maximum audio output amplitude.
Sensitivity
1. UUT set to FM mode CH22, output of RF signal generator connect to TP5 (Antenna).
2. Set RF S.S.G Freq.: 27.225MHz, Mod.: ±1.2KHz，Fmod.: 1KHz, Output level:0.5uV.
3. Adjust the volume control for 2V output on distortion meter read.
4. Adjust L2 & L3 for more than 12dB at SINAD meter.
T-Squelch Sensitivity
1. UUT set to AM CH22, output of RF signal generator to the antenna input terminal.
2. Set RF S.S.G Freq.: 27.225MHz，Mod.: 60%，Fmod.: 1KHz, Output level: -47dBm.
3. Volume control and Squelch control set to maximum position.
4. Adjust the RV5 to mute the speaker, then slowly turn RV5 to a position that the audio output on the speaker
just appears from no output. Turn the RF S.S.G. output level to -57dBm, the audio must be off from the
speaker.
RX Signal Meter Display
1. UUT set to AM CH22，output of RF signal generator to antenna input terminal. RF Gain volume at maximum.
Power switch turn on.
2. Turn the RF S.S.G output for 100uV without modulation.
3. Adjust RV6 for 9 characters displayed at the RX signal strength of the LCD.
4. Turn the RF S.S.G level output increase 30dB, the RX signal strength should up to +30 position.
Model No: 19 DX4 EU

ALIGNMENT PROCEDURE

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