HP 8562E, Service Manual

Page: 437 / 482

Al4 Frequency Control Assembly
The block diagrams for the Al4 and Al5 assemblies are located in Chapter 11,
“Synthesizer Section.”
Refer to function block Z on the Al4 Frequency Control Schematic Diagram (sheet 3 of 5) in
the
HP 8560 E-Series Spectrum Analyzer Component Level Information.
1. Set the HP 85623 to the following settings:
Center frequency
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...300 MHz
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. On the HP 85623, press and measure the signal power at the output of A7
(see item (1) of Figure 12-3).
3. If the output power is low, the output voltage of at pin 14 (item (2) of
Figure 12-3) should be above 0 V. If the output power is high, the voltage should be more
negative than -10 V. If the voltages do not measure as indicated, check that the voltages
at
pins 5 and 13, item
are consistent with the operational amplifier output.
If a TAM is available, use Manual Probe Troubleshooting to make
measurements on
pins 5, 13, and 14. These voltages are referred to as
AMP CNTL, LO SENSE, and PIN respectively.
4. If the voltages measure as indicated in step 3, measure the All YTO output. (See item (3)
of Figure 12-3.)
5. If all measurements are within limits, refer to “A7 LO Distribution Amplifier” in this
chapter.
RF Section 1