4-32 Service Guide E8364-90038
Troubleshooting PNA Series Microwave Network Analyzers
Measurement System Troubleshooting E8362C, E8363C, E8364C
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”.
Checking the A12 Output, All Bands
1. Disconnect W1 from A12.
2. Connect a cable to A12 and measure the output power. A power level of a -17 dBm ±5 dB indicates the
A12 assembly is functioning normally.
3. If the output power of A12 is at or below the minimum power level, replace the A12 source 20 assembly.
4. If the output power is normal, reconnect cable W1 to A12.
Checking the A21 Output (E8363C and E8364C Only)
1. Disconnect W2 from A21.
2. Connect a cable to A21 and measure the output power. A power level of a -7 dBm ±5 dB indicates the
A21 assembly is functioning normally.
3. If the output power of A21 is at or below the minimum power level, replace the A21 SOMA 50 assembly.
4. If the output power is normal, reconnect cable W2 to A21.
Checking the A10 5 MHz Reference Output, All Bands
1. Refer to the block diagram at the end of this chapter and to “Top Cables–All, All Options Except 080” on
page 6-16. Locate flexible cable W31, at the A10 frequency reference board.
2. Disconnect W31 from A10J10.
3. Connect the spectrum analyzer to A10J10.
4. The spectrum analyzer should measure a signal at 5 MHz.
5. If no 5 MHz signal is present, replace the A10 frequency reference board. Refer to “Removing and
Replacing the A6, A8, A9, and A10 Boards” on page 7-18.
To Next Page
Loading...
Need help?
General
