3 SERVICE T2130
3.5.3 TX-PROCESSOR (MODULE 3)
3.5.3.1 A/D CONVERTER
REFERENCE VOLTAGE
Test set-up: Mode 1.
A. Connect a Voltmeter to pin 13 on U15, (4053).
Voltage is +2.5 Volt +/- 1.5%.
B. Connect a Voltmeter to pin 7 on U16/2, (TL072).
Voltage is +5.0 Volt +/- 1.7%.
VFORWARD MEASURING
Test set-up: Mode 2.
A. Select a frequency near 1650 kHz.
Connect a voltmeter to the upper end of R56, (3K92). Key the microphone and whistle into the
microphone. Note the voltmeter reading (approx. 10V) Release the key while whistling.
B. Enter SP-22-0.
Compare the displayed Vforward to the measured voltage. Maximum deviation from the measured
voltage is +/-4%.
SWR MEASURING
Test set-up: Mode 2.
A. Enter SP-29.
Connect a Voltmeter to the upper end of R56, (3K92). Vforward voltage should be approx. 7.3 Volt
DC.
B: Connect a Voltmeter to the upper end of R65, (3K92). Vreverse voltage should be
approx. 0.12 Volt DC. Leave SP-29 by entering the ‘ENT’ key.
C: Calculate the SWR.
Vforward + Vreverse
SWR = ----------------------------
Vforward - Vreverse
D. Enter SP-23-0 >ENT<.
Compare the displayed SWR to the calculated voltage. Maximum deviation from the calculated is
+12%/-5%.
+24 VOLT SENSE MEASURING
Test set-up: Mode 2.
A. Connect a Voltmeter to the upper end of R63, (15K4).
B: Enter SP-29. Read the voltmeter. Leave SP-29 by entering ‘ENT’. Calculate the battery voltage:
‘+24 Volt Sense’ + 0.95
Vbattery = ----------------------------------
1.31
Enter SP-20-0 >ENT<.
C: Compare the displayed battery voltage to the calculated voltage. Maximum deviation
from the calculated is +/-5%.
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