Agilent Technologies 856290216 service manual General Troubleshooting

489 RBW 100 Unable to adjust 100 Hz resolution bandwidth.

490 RBW 100 Unable to adjust 100 Hz resolution bandwidth.

491 RBW C300 Unable to adjust the resolution bandwidths less than 300 Hz. Crystal sweep gain problem.

492 RBW 300 Unable to adjust 300 Hz resolution bandwidth. Crystal sweep gain problem.

493 RBW 1K Unable to adjust 1 kHz resolution bandwidth. Crystal sweep gain problem.

494 RBW 3K Unable to adjust 3 kHz resolution bandwidth. Crystal sweep gain problem.

495 RBW 10K Unable to adjust 10 kHz resolution bandwidth. Crystal sweep gain problem.

496 RBW 100 Unable to adjust 100 Hz resolution bandwidth. Inadequate Q.

497 RBW 100 Unable to adjust 100 Hz resolution bandwidth. Alignment problem.

498 RBW 100 Unable to adjust 100 Hz resolution bandwidth. Gain problem.

499 CAL UNLK Cal oscillator is unlocked. Verify the unlocked conditions as follows:

1.Place A4 in its service position and disconnect W51 (gray-yellow) from A4J7.

2.Connect W51 to the input of another spectrum analyzer. This is the 10 MHz reference for the cal oscillator.

3.If a 10 MHz signal (approximately 0 dBm) is not present, suspect the Al5 RF assembly, the A21 OCXO, or the Al5 assembly TCXO (Option 103). If the 10 MHz reference is present, continue with step 4.

4.Reconnect W17 to A4J7 and monitor the tune voltage at A4J9 pin 3 with an oscilloscope.

5.Press (PRESET) on the spectrum analyzer under test.

6.If the voltage is either +15 Vdc or -15 Vdc, the Cal Oscillator is probably at fault. Normally, the voltage should be near +15 V during a sweep, and between -9 V and +9 V during retrace.

An intermittent error 499 indicates the cal osc phase-locked-loop probably can lock at 10.7 MHz, but cannot lock at the 9.9 and

11.5MHz extremes. This may prevent the cal oscillator from adjusting the 1 MHz or 30 kHz through 300 kHz bandwidths. This symptom implies a failure in the oscillator, function block X. (See the A4 log amp/Cal oscillator schematic sheet 4 of 4.) The oscillator is unable

to tune the required frequency range with the -9 V to +9 V control voltage. Troubleshoot A4CR802 (most probable cause), L801, C808, C809, and U807.

500 AMPL 30K Unable to adjust amplitude of 30 kHz resolution bandwidth.

501 AMPL .lM Unable to adjust amplitude of 100 kHz resolution bandwidth.

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