Keysight N5171B EXG Service Manual page 104

Troubleshooting
Checking ALC Operation < 3.2 GHz (N5173B/83B)
5. Record the voltage in
6. Measure the J18 connector center pin voltage at the remaining signal
7. Record the voltages in
8. Turn off the RF (press RF On/Off to Off).
9. Measure the J18 connector center pin voltage.
10.Record the measured voltage in
11.Compare the measured voltages to the voltages listed in the Example
12.Go to
Keysight X-Series Signal Generators Service Guide
generator amplitude settings shown in
Table 1-5
Power Level
0 dBm
–10 dBm
–20 dBm
-30 dBm
RF Off
Voltages column in Table
— If the measured voltages do not decrease by approximately 1V for
each 10 dBm reduction in power level, as shown in the Example
Voltages column in the table, or if there is no change in the voltage
when changing power levels:
a. Replace the A7 Micro Deck.
b. Go to Chapter 4, "Post-Repair Procedures and Operational
Performance
— If the measured voltages decrease by approximately 1V for each 10
dBm reduction in power level, as shown in the Example Voltages
column in the table, verify the continuity of the W23 modulator
drive cable (see
— If the cable is bad, replace the cable.
— If the cable is good, replace the RF assembly.
Chapter 4, "Post-Repair Procedures and Operational Performance
Verification.".
Table 1-5.
Table
Table 1-5.
Table 1-5.
Measured Voltage Comparison
Example Vol tages
+1.45 V
+0.275 V
–0.950 V
-1.87 V
Decreases output voltage
more than -3.05 V
1-5.
Verification.".
Figure 1-20) to the A3 RF assembly.
1-5.
Measured Vol tage
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