Glenayre GL-T8541, Руководство пользователя, Страница: 71 / 90

Glenayre Document Number: 9110.01002 GL-T8541 PA
09/10/99 CHECKOUT AND MAINTENANCE
t8541
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Copyright © 1997 Glenayre Page: 7-17
7.11.2.2 Checking Driver Board Q1
1. Remove power from transmitter.
2. Remove metering board fuses F3, F6, and F8 (to 28 V from PAs 1, 2, and 3
respectively). Refer to Figure 7-1.
3. Remove the PA module from the transmitter chassis.
4. Remove the outer and inner PA covers.
5. Refer to Figure 7-9. Remove the RF jumper (to open the RF path between Q1 and
Q2).
6. Remove L6 (to disc28 volts from drain of Q2).
7. Solder coax cable shield to ground pad and center conductor to Q1 RF output pad, as
shown in Figure 7-9.
8. Reinsert the PA module into the transmitter chassis.
9. Connect the other end of the coax cable through a wattmeter and to a 50-ohm test
load, refer to Figure 7-8.
10. Reconnect power to transmitter.
11. Key the exciter using VDT main menu sequence 9-1-1.
12. The output of Q1 should be between 1.5 and 2.5 watts, depending on the RF output of
the exciter and the R6 bias setting for Q1.
13. Unkey transmitter, remove power from transmitter, replace metering board fuses
removed in step 2, and reassemble the driver board and PA module.
Figure 7-8 Driver Board Q1 Test Setup Block Diagram
VDT
DSP
Exciter
Driver
Board
RF Wattmeter
RF Test
Load
Short length of low-loss
RF cable
Q1 Output
PA Module