LXT110
ALIGNMENT PROCEDURE
Page 1
1. REFERENCE TEST EQUIPMENT
A. HP8921A Cell site test set or HP8920A, B Communication Test Set with Spectrum
Analyzer option.
B. Fluke 187 Digital Voltmeter
C. HP E3615A Power supply
2. TEST POINT
A. ANTENNA : Test point is not prepared. Use antenna contact with
ANTENNA_GND_T(antenna ground).
B. VCO reference voltage : Test point TP1 is prepared.
C. RX audio output : Test point SPKOUT is prepared or use ear-jack(3.5mm).
D. TX Mic. Input : Test point MICIN is prepared or use ear-jack(2.5mm) with 10uF
coupling capacitor.
E. Battery Vcc : Test point TP2 is prepared.
F. Up Key : Test point UP is prepared.
G. Down Key : Test point DW is prepared.
H. Function Key : Test point Menu is prepared.
I. Monitor Key : Test point SCAN is prepared.
J. PTT Key : Test point PTT is prepared.
Note. : All key can be activated when connect with ground.
3. VCO ALIGNMENT
A. Set unit to Channel 1 and connect a voltmeter to TP1 (VCO PD).
B. Press & hold PTT.
C. Extend L303 until the voltmeter reads 1.2V.
D. Cover shield-plate on VCO can and monitor the voltage on TP1. The voltage should be
1.2Vdc +/-0.2Vdc. If the voltage is not 1.2Vdc +/-0.2Vdc, realign L303 until meet to
requirement.
E. Release PTT button so units is in receiving mode and monitor the voltage on TP1. The
voltage should be in the range 1.0Vds +/-0.3V
F. Set unit to channel 14.
6. Press & hold the PTT switch and observe the voltage on TP4. The voltage should be 1.5 –
2.5 Vdc.
7. Release PTT and observe the voltage on TP4. The voltage should read between 1.5 - 2.5
Vdc.
Note : VCO shield-can should be soldered after VCO alignment is finished.
4. TRANSMITTER FREQUENCY ALIGNMENT
A. Press & hold the PTT button.
B. Align CT201 trimmer capacitor such that the output frequency is equal to the channel
frequency with a maximum error of +/- 200 Hz. CT201 is located on the left side of
20.95MHz X-tal.
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