Midland 4001 Alignment Instructions

8. ALIGNMENT INSTRUCTIONS
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
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- TX no mod
Check voltage at TP1
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Adjust L501 until voltage at TP1 to be equal to 4 volt
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8.2.TX frequency

Set unit chanel 20
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TX no mod
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- Measure frequency
Adjust CT201 until frequency to be equal to 27.205MHz
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If can not measure frequency skip to adjust TX power and return to this
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methode next time

8.3.TX power

Set unit chanel 20 mic gain maximum
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Adjust L502,L10,L11 and L6 downward for minimum
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- Adjust L11 upward 1 round ( 360° )
TX with mod 1.25KHz up 20 dB
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See signal at oscilloscope
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Adjust L10 upward for maximum
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Adjust L11 again for maximum
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- TX no mod
Adjust C607 for maximum power
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Adjust RV102 until TX power to be equal to 3.8 volt
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8.4.TX AM modulation

Set unit chanel 20 mic gain maximum
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- TX with mod 1KHz up 20 dB
Measure % modulation
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Adjust RV 201 for modulation 90%
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TX with mod 1KHz down20 dB
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Measure % modulation
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- Adjust level at CR oscilator until % modulation to be equal to 30%
TX with mod 1KHz up 20 dB
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If % modulation not equal with 90% back to adjust RV 201 again
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MIDLAND 4001