Midland 4001 User Manual

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

Midland 4001 Specifications

General

Brand	Midland
Model	4001
Category	Radio
Language	English

Summary

VCO Locking Voltage

VCO Locking Voltage Adjustment

Adjust L501 to set TP1 voltage to 4 volts for VCO locking.

TX Frequency

TX Frequency Adjustment

Adjust CT201 to achieve 27.205MHz TX frequency.

TX Power

TX Power Adjustment

Adjust L502, L10, L11, L6, C607, and RV102 for optimal TX power.

TX AM Modulation

TX AM Modulation Adjustment

Adjust RV 201 and CR oscillator for 90% and 30% modulation.

TX S-meter

TX S-meter Adjustment

Adjust RV 202 to set the TX S-meter to 4 watts.

AWI

AWI Adjustment

Adjust RV 301 to turn off D306 (LED AWI) for proper AWI function.

RX Sensitivity

RX Sensitivity Adjustment

Adjust L4, L1, L2, L3 for maximum RX sensitivity.

Squelch

Squelch Adjustment

Adjust RV 101 until a signal appears on the oscilloscope for squelch.

RX S-meter

RX S-meter Adjustment

Adjust RV 103 to set the RX S-meter to S-9.