a. Set the spectrum analyzer (LINE) switch OFF, disconnect W13 from A14J12, and set
the luNE) switch ON.
b. Wait for the power-on sequence to finish and then set the spectrum analyzer settings to
the following:
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...3 GHz
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz
c. If the DVM measures -15 Vdc
ho.2
V, the Al3 second converter is probably defective.
If the DVM measures outside this limit, the Al4 frequency control assembly is
probably defective.
9. Set the
luNE)
switch OFF and reconnect W13 to A14J12.
10. Remove the test cable from A13J2 and reconnect W35 to A13J2.
11. Disconnect W33 (coax 81) from A13J4 and connect W33 through a test cable to the input
of another spectrum analyzer.
12. Tune the other spectrum analyzer to a center frequency of 600 MHz.
13. If a 600 MHz signal is not present, or its amplitude is less than -5
dBm,
the fault is
probably on the Al5 RF assembly.
14. Reconnect W33 to A13J4.
15. Connect the positive lead of a DVM to A14J19 pin 15 and the negative lead to A14J19
pin 6.
16. If the DVM does not measure between
t14.0
Vdc and i-15.0 Vdc, perform the following:
a. Press [LINE) to turn spectrum analyzer off and disconnect W13 from A14J12.
b. Press
m
to turn spectrum analyzer on and set the spectrum analyzer to the
following settings:
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..300MHz
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lO MHz
c. The voltage should measure
+15
Vdc f0.2 V. If the voltage measures outside this
limit, the Al4 frequency control assembly is probably defective.
d. Press (LINE to turn spectrum analyzer off. Reconnect W13 to A14J12, and press (LINE)
to turn spectrum analyzer on. Set the HP 85623 to the following settings:
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
..300MH~
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz
17. Move the positive lead of a DVM to A14J19 pin 1. The voltage should measure between
-150
mVdc
and -800
mVdc.
If the voltage measures outside this limit, the Al3 Second
Converter is probably defective.
12-10 RF Section