163
RF Section Troubleshooting
Troubleshooting
7. YTF Preselector Control Logic Verification
(All except Option 503)
NOTE In order to properly measure the preselector tune output from the A15 Front
End Control Assembly, the following items are required:
— E9637A Banana plug to BNC (f) adapter
— E9632A BNC (M) to SMA (f)
— 8120-1460 Small coaxial cable SMA (m) to mmcx (m)
Connect the mmcx end of the cable to A15J300, preselector tune output at the
upper left corner of A15 Front End Control Assembly.
Press Single on the analyzer. Verify the voltages in Table 4-8 as the center
frequency of the analyzer is changed.
NOTE Tolerances can be used as a guideline. The true test is whether or not the
analyzer will function and meet published specification.
If any of the preselector tune voltages do not match the levels shown in Table
4-8, the most probable causes are a misaligned YTF or the A15 Front End
Control Assembly. Perform the YTF characterization (press System,
Alignments, More, Ad vanced, Characterize Preselector).
To further test the YTF control current, select Amps on the DVM and place the
positive lead of the DVM on one of the YTF Coil Current P8 pins and the other
DVM lead to the other Coil Current pin.
Table 4-8 YTF Tune Voltages
Center Frequency
(GHz)
~ Tune Voltage
(VDC)
Tolerance
(VDC)
5.0 1.6 ±0.5
10
a
3.228 ±1.0
15
b
4.85 ±1.0
20
b
6.5 ±1.0
26
b
8.45 ±1.0
a. Options 513 and 526
b. Option 526
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