588 Chapter11
RF Section
Low Band Problems
Low Band Problems
1. On the HP 8560E/EC, press PRESET and REALIGN LO &IF. If any
error messages are displayed, refer to "Error Messages" in Chapter
6.
2. Perform "External Mixer Amplitude Adjustment" in Chapter 2. If
this adjustment cannot be completed, perform the steps located in
"Third Converter" in this chapter.
3. Perform the "First LO Output Amplitude" performance test. (Refer
to the HP 8560 E-Series Spectrum Analyzer Calibration Guide or use
the TAM functional test.)
4. If the performance test fails, perform the "First LO Distribution
Amplifier Adjustment" in Chapter 2. If the adjustment fails, set the
HP 8560E/EC to the following settings:
5. Place the jumper on A14J23 in the TEST position. Remove W38 from
the input of the A7 LODA.
6. Use a power meter or another spectrum analyzer to measure the
output of A11 YTO. The power should be between +2 dBm and +13
dBm.
7. Reconnect W38 to the LODA. Place the jumper on A14J23 in the
NORM position.
8. If ERR 334 (unleveled output) is present and the A11 YTO power
output is correct, the A7 LODA drive circuit may be defective. Refer
to "A7 LODA (LO Distribution Amplifier)" in this chapter.
9. Troubleshoot the signal path. Refer to the power levels listed on
Figure 11-5 on page 615, RF Section Troubleshooting Block
Diagram.
10.Check Third Converter as follows:
a. On the HP 8560E/EC, press
PRESET and set the controls as
follows:
Center frequency .................................................300MHz
Span .............................................................................0Hz
b. Inject a −28 dBm, 310.7 MHz signal into A15J801.
c. If a flat line is displayed within 2 dB of the reference level, but the
"External Mixer Amplitude Adjustment" fails, troubleshoot the
A15 RF assembly.
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