Agilent Technologies E8362A, Service Manual

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Service Guide E8364-90001 4- 39
PNA Series Microwave Network Analyzers Troubleshooting
E8362A, E8363A, E8364A Measurement System Troubleshooting
A phase lock problem is due to either:
• faulty RF signal generation (caused by the A12 source 20, A21 SOMA 50, A23 and A24
SOMA 70)
• faulty LO signal generation (caused by the A8, A10, A11, A17 or A18 board)
RF Signal Troubleshooting
To isolate a broadband RF signal generation failure, check the test port output power:
1. Connect a power meter and power sensor to Port 1 of the analyzer.
2. On the analyzer, press Preset , set the Center Frequency to 2 GHz , and the Frequency
Span to 0 Hz . Note the power reading displayed on the power meter. The output power,
as indicated on the power meter, should be approximately
−
12 dBm ±5 dB for an
analyzer with no hardware options or -17 dBm ±5 dB for an analyzer with options.
NOTE In the unlocked state, the analyzer will “search” for the reference signal.
3. Connect the power sensor to Port 2 and set trace to measure S
22
. Note the power
reading displayed on the power meter. The power meter reading should be the same as
was measured at Port 1.
• If the power level is low at both test ports the problem is either the A12 source 20 or the
A21 SOMA 50. Continue with “Checking the A12 Output, All Bands” .
• If the output power is high at both test ports the problem is LO signal related. Continue
with “LO Signal Troubleshooting” .
LO Signal Troubleshooting
To isolate a broadband LO signal, refer to the data obtained from the “Serial Bus Test” on
page 4-32 :
• If the data obtained for the A10 frequency reference board is out of tolerance, continue
testing at “Checking the A10 5 MHz Reference Output” on page 4-40 .
• If the data obtained for the A10 frequency reference board is correct but the data for the
A8 fractional-N synthesizer board is out of tolerance, continue testing at “Checking the
A8 Fractional-N Synthesizer Band 1 Output” on page 4-41 .
• If the data obtained for the A8 fractional-N synthesizer board is correct—and “RF
Signal Troubleshooting” has been performed—but there is still a phase lock problem,
continue testing at “Checking the A17 LOMA 10 Output” on page 4-42 .
Checking the A12 Output, All Bands
1. Disconnect W1 from the A12 source 20.
2. Connect a cable to the A12 connector and measure the output power. A power level of
−
17 dBm
±
5 dB indicates the A12 source 20 is functioning normally.
3. If the output power level is at or below the minimum power level for the power sensor,
replace the A12 source 20.
4. If the signal is present, reconnect cable W1 and continue testing at “Checking the A21
Output, All Bands” on page 4-40 .