Warning : Any repairs or adjustment should be made under the supervision of a
qualified radio-telephone technician.
8.1.VCO locking voltage
- Set unit chanel 40
- TX no mod
- Check voltage at TP1
- Adjust L501 until voltage at TP1 to be equal to 4 volt
8.2.TX frequency
- Set unit chanel 20
- TX no mod
- Measure frequency
- Adjust CT201 until frequency to be equal to 27.205MHz
- If can not measure frequency skip to adjust TX power and return to this
methode next time
8.3.TX power
- Set unit chanel 20 mic gain maximum
- Adjust L502,L10,L11 and L6 downward for minimum
- Adjust L11 upward 1 round ( 360° )
- TX with mod 1.25KHz up 20 dB
- See signal at oscilloscope
- Adjust L10 upward for maximum
- Adjust L11 again for maximum
- TX no mod
- Adjust C607 for maximum power
- Adjust RV102 until TX power to be equal to 3.8 volt
8.4.TX AM modulation
- Set unit chanel 20 mic gain maximum
- TX with mod 1KHz up 20 dB
- Measure % modulation
- Adjust RV 201 for modulation 90%
- TX with mod 1KHz down20 dB
- Measure % modulation
- Adjust level at CR oscilator until % modulation to be equal to 30%
- TX with mod 1KHz up 20 dB
- If % modulation not equal with 90% back to adjust RV 201 again
8. ALIGNMENT INSTRUCTIONS MIDLAND 4001
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