Agilent Technologies 8719ET Service Manual page 232

Source Troubleshooting
Band-Related Problems
5. Check all RF cabling and connections.
• If any of the cables or connectors are bad, have them repaired or replaced.
• If the cables and connectors are good, replace the A55 YIG 1. If mid band problems
still persist, then replace the A58 M/A/D/S.
High Band Problems: (8719ET/ES and 8720ET/ES Only)
1. Press the following:
SERVICE MENU
System
SRC ADJUST MENU
(SRC tune in the high band is capable of tuning the instrument from about 2.4 to
5 GHz). Loss of lock in high band only may likely be due to a bad cable or connection.
2. The following components may be at fault. Refer to the overall block diagram at the end
of Chapter 4 for information.
A5 (source switch)
3. Since the analyzer phase locked in lowband, all of the phase lock circuitry is working
Look for low power as a cause of phase lock errors.
4. Check power at A5J3.
• If the power at A5J3 is less than 0 dBm, check the insertion loss of A5 (source
switch), A6 (source switch), and the associated cabling.
• If the power at A5J3 is greater than 0 dBm, the problem is probably above 5 GHz.
Proceed with the next steps.
5. Check all RF cabling and connections.
• If any of the cables or connectors are bad, have them repaired or replaced.
• If the cables and connectors are good, replace the A55 YIG 1. If high band problems
still persist, then replace the A58 M/A/D/S.
High Band Problems: (8722ET/ES Only)
1. Press the following:
SERVICE MENU
System
SRC ADJUST Menu
(SRC tune in the high band is capable of tuning the instrument from about
19.5 to 24 GHz.) Loss of lock in high band only may likely be due to a bad cable or
connection.
7-24
SERVICE MODES
DAC NUM HIGH BAND
A6 (source switch)
SERVICE MODES
DAC NUM HIGH BAND
4000 x1
A58 M/A/D/S A55 YIG 1
4000 x1
8719ET/20ET/22ET
8719ES/20ES/22ES
RF Network Analyzers
Service Guide