Agilent Technologies 8753ES, Service Manual

Page: 350 / 617

Chapter 7 7-13
Source Troubleshooting
Phase Lock Error
4. Verify the remaining CW frequencies, comparing the counter reading with the value in
Table 7-2 :
• Press .
• Press .
5. Press to count the frequency of the 2nd LO signal.
6. Press . Verify that the counter reading matches the
corresponding 2nd LO value for the CW frequency. (Refer to Table 7-2 .)
7. Verify the remaining CW frequencies, comparing the counter reading with the value in
Table 7-2 :
• Press .
• Press .
8. Press to count the frequency of the PLREF signal.
9. Press . Verify that the counter reading matches the
corresponding PLREF value for the CW frequency. (Refer to Table 7-2 .)
10.Verify the remaining CW frequencies, comparing the counter reading with the value in
Table 7-2 :
• Press .
• Press .
11.Check the results.
• If all the counter readings match the frequencies listed in Table 7-2 , skip ahead to
“A13/A14 Fractional-N Check” on page 7-20 .
• If the counter readings are incorrect at the 500 kHz and 2 MHz settings only, go to
“FN LO at A12 Check” on page 7-16 .
• If all the counter readings are incorrect at all three CW frequencies, the counter may
be faulty. Perform the “Oscilloscope Method” check of the signals described next. (If
the signals are good, either the A10 or A14 assemblies could be faulty.)
Table 7-2 Analog Bus Check of Reference Frequencies
CW Frequency Analog Bus Node 21
100 kHz
Analog Bus Node 24
2nd LO
Analog Bus Node 25
PLREF
500 kHz 0.100 MHz 0.504 MHz 0.500 MHz
2 MHz 0.100 MHz 2.007 MHz 2.000 MHz
50 MHz 0.100 MHz 0.996 MHz 1.000 MHz
NOTE: The counter should indicate the frequencies listed in this table to within
±
0.1%.
Accuracy may vary with gate time and signal strength.
2 M/
µ
50 M/
µ
24 x1
Menu
CW FREQ
500 k/m
2 M/
µ
50 M/
µ
25 x1
Menu CW FREQ 500 k/m
2 M/
µ
50 M/
µ