20. Last Converter Adjustments
15. Move the probe to the access hole above
(the
rightmost access hole). Adjust
(second access hole
from the right) to minimize the amplitude of the 321.4 MHz signal
displayed on the second spectrum analyzer.
16. With the probe still in
the
access hole above
adjust
(center access hole) to maximize the amplitude of the
32 1.4 MHz signal displayed on the second spectrum analyzer.
17. Adjust
(second access hole from the left) to minimize
the amplitude of the 321.4 MHz signal displayed on the second
spectrum analyzer.
18. Adjust
(left-most of
the
five access holes) to maximize
the amplitude of the 321.4 MHz signal displayed on the second
spectrum analyzer.
19. Remove the probe from the access hole above
and
disconnect the probe from the BNC to SMB snap-on test cable.
Use the BNC to SMB snap-on test cable to connect the RF INPUT
of the second spectrum analyzer to
(21.4 MHz OUT).
20. Set the spectrum analyzer controls as follows:
CENTER FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7 MHz
FREQUENCY SPAN . . . . . . . . . . . . . . . . . . . . . . . .
REFERENCE LEVEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -30
21. On the synthesized sweeper, key in
310.7 MHz,
[
POWER LEVEL
]
-40
22. Locate the 10.7 MHz Notch Filter adjustment, visible through the
remaining unlabeled access hole near the center of the bottom
cover of the
Last Converter Assembly (refer to Figure 3-88).
Adjust
to minimize the amplitude of the 10.7 MHz
signal displayed on the second spectrum analyzer.
23. Set the RF Section LINE switch to STANDBY.
24. Disconnect
the
synthesized sweeper from
321.4 MHz IN.
Disconnect the second spectrum analyzer from
(21.4 MHz
OUT).
Disconnect cable 2 (red) from
300 MHz IN.
25. Disconnect cable 2 (red) from
300 MHz OUTPUT and
cable 85 (gray/green) from
100 MHz INPUT. Remove the
Phase Lock Assembly, the
Miscellaneous Bias/Relay
Driver Assembly, the
Slope Generator Assembly, and the
YTX Driver Assembly from the RF Section.
26. Reinstall the
Last Converter Assembly in the RF Section,
and replace the two screws attaching the
Last Converter
Assembly to the RF Section chassis. Replace
the
RF Section right
side cover.
27. Reconnect cable 1 (brown) to
321.4 MHz IN, cable 2 (red)
to
300 MHz IN, and cable 81 (gray/brown) to
(21.4 MHz OUT) on the
Last Converter Assembly.
28. Reinstall the
Phase Lock Assembly, the
Miscellaneous Bias/Relay Driver Assembly, the
Slope
3-172 Adjustments
