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

8.5.TX s-meter
-Set unit chanel 20
-TX no mod
-See s-meter
-Adjust RV 202 until s-meter to be equal to 4 watt
8.6.AWI
-Set unit chanel 20 mic gain maximum
-TX with mod up 20 dB
-See D306 ( LED AWI )
-Adjust RV 301 until D306 off
-Check AWI
-If AWI not operate back to adjust RV 301 again
8.7.RX sentivity
-Set SSG frequency 27.185 MHz AM 60% mod
-Set unit chanel 19 RF gain maximum,squelch minimum,control volume 2 volt
-Measure sentivity
-Adjust L4 downward for minimum
-Adjust L1,L2,L3 for maximum sentivity
8.8.Squelch
-Set SSG frequency 27.185 MHz AM 60% mod level –57 dBm
-Set unit chanel 19 RF gain maximum,squelch maximum,control volume 2 volt
-See signal at oscilloscope
-Adjust RV 101 until appear signal at oscilloscope
8.9.RX s-meter
-Set SSG frequency 27.185 MHz AM 60% mod level –67 dBm
-Set unit chanel 19 RF gain maximum,squelch minimum
-See s-meter
-Adjust RV 103 until s-meter to be equal to s-9