Troubleshooting
Troubleshooting Unlevels
1-52
adjusted to this level, troubleshoot the RF path.
• Remove the cable from J3 on the A10 ALC and measure the dc voltage on the center pin of the cable.
The dc voltage should be -.150 mVdc .05 Vdc.
• Set the power level to 0 dBm and repeat the center pin measurement. The voltage should be -30
mVdc 10 mVdc.
• If the voltages are good, go to step 8.
• If the voltages are the same, replace the A25 Highband Coupler/Detector.
8. Unleveled only between 3.2 GHz and 20 GHz or 40 GHz.
If the unleveled condition occurs between 3.2 GHz and 20 GHz or 40 GHz, the problem is most likely the
A30 Modulation Filter.
a. Checking the A30 Modulation Filter.
• Set the signal generator to 20 GHz or a frequency where the signal generator is unleveled and
measured RF output level is +7 dBm. If the power can not be set to +7 dBm, troubleshoot the RF
path.
• Remove the cable going to J4 on the A30 Modulation Filter and measure the voltage on the center
pin. The voltage should be approximately +4.7 Vdc.
• Set the amplitude to -15 dBm. The voltage on the center pin should decrease a few mVdc.
• If the voltages are good, replace the A30 Modulation Filter.
• If the voltages are bad, go to step 7.
9. Unleveled only between 20 GHz and 40 GHz.
If the unleveled condition occurs between 20 GHz and 40 GHz, the problem is either with the A27 40 GHz
Doubler or the A25 Highband Coupler/Detector.
a. Checking the A25 Highband Coupler/Detector
• Using a spectrum analyzer, check at the RF output signal level to the level shown in the Maximum
Leveled Power table. The RF output level must be greater than the maximum specified power level.
• If the maximum power level is not greater than the maximum power level specified, troubleshoot
the RF path starting with the signals out of the A30 Modulation Filter to the A27 40 GHz Doubler.
• If the signal is greater than the maximum specified power level, replace the A25 Highband
Coupler/Detector.
10.Unleveled at all frequencies.
If the signal generator is unleveled at all frequencies, the problem is most likely the A10 ALC.
a. Checking the A10 ALC.
• Run a complete self-test and troubleshoot the reported failure.
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