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Models 8672S/86720A
Adjustment
5-6. LOW BAND ADJUSTMENTS (10 MHz to 2 GHz) (cont'd)
Procedure
4.
Connect digital voltmeter to A9TP1 on the ALC Power Supply board. Adjust A9R11
(cont'd)
for -10 ± 0.005 Vdc reading.
5. Connect digital voltmeter to A9TP2. Adjust A9R4 for +20 ± 0.005 Vdc reading. This
completes the ALC power supply adjustments.
NOTE
In the following steps, make sure the voltmeter G UARD is released. The
voltage in step 6 is not critical and will change slightly depending upon
temperature.
6.
Connect voltmeter to the
<f>
LOCK test point on the 4.2 GHz local oscillator. Adjust
the oscillator tuning screw (under the attenuator) for an 8.0 ± 0.4 Vdc reading.
7.
Set the Signal Generator to 300 MHz at 0 dBm. Set the OUTPUT VERNIER on the
FEU fully CCW.
8. Connect voltmeter to A10TP4 and verify the voltage reading is -6.2 Vdc ±30 mVdc.
Record the reading.
Vdc
NOTE
Before programming any specific commands, be sure the FEU is in the
remote enabled mode.
9.
Program the FEU vernier to -12 dBm by sending the the program string "A1234".
10. Adjust A10R35 (OdB) for the same voltage reading recorded in step 8 (± ImVdc).
11. Connect the voltmeter between A10TP2 and A10R4 (51.1 ohms) as shown in Figure
5-2.
12. Adjust A10R13 (IQS) for a voltage reading of 0 ± 10 ^ivdc.
13. Set the Signal Generator RF OUTPUT switch ON.
14. Connect the voltmeter to A10TP5. Adjust A10R58 (IOFFS) for a voltage reading of
130 ± 1 mVdc.
15. Set the Signal Generator RF OUTPUT switch OFF. Verify the FEU LVL UNCAL
indicator lights.
NOTE
Steps 16 and 1
7
calibrate the front panel meter. They do not change the
power output.
16. Program the FEU vernier to -10 dBm by sending the string "A134B2". Adjust
A10R115 (MZ) to set the meter to -10 dBm.
5-3
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