596 Chapter11
RF Section
A14 Frequency Control Assembly
A14 Frequency Control Assembly
NOTE The block diagrams for the A14 and A15 assemblies are located in
Chapter 10, "Synthesizer Section."
A7 LODA Drive
Refer to function block Z on the A14 Frequency Control schematic in
the
HP 8560 E-Series Spectrum Analyzer Component Level Information.
1. Set the HP 8560E/EC to the following settings:
Center frequency ......................................................300MHz
Span ..............................................................................2MHz
2. On the HP 8560E/EC, press
SGL SWP and measure the signal power
at the output of A7 (see item (1) of Figure 11-2 on page 597).
3. If the output power is low, the A14U429B output voltage at A14J18
pin 14 (item (2) of Figure 11-2 on page 597) should be greater than 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 A14J18 pins 5 and 13, item (4), are consistent with
the output of the operational amplifier.
NOTE If a TAM is available, use Manual Probe Troubleshooting to make
measurements on A14J18 pins 5, 13, and 14. These voltages are
referred to as AMP CNTL, LO SENSE, and PIN ATTEN respectively.
4. If the voltages measure as indicated in step 3, measure the A11 YTO
output. (See item (3) of Figure 11-2 on page 597.)
5. If all measurements are within limits, refer to "A7 LODA (LO
Distribution Amplifier)" in this chapter.
To Next Page
Loading...
Need help?
General
