18. RF Module Phase Lock Adjustments
6. Connect the DVM to
and connect the DVM ground to
the metal case/shield of the
Phase Lock Assembly. Refer to
Figure 3-82 for the location of
and
7. Note
the
DVM indication at
Voltage at
Vdc
8. Connect the DVM to
and note the DVM indication.
Voltage at
Vdc
9. Add
the
voltage measured in step 7 to the voltage measured
in step 8. The absolute value of the resulting sum should be
less than 0.20 Vdc. If the resulting sum is greater than 0.20
Vdc, suspect a failure of
Sampler or related circuit
components.
The voltage at
should fall in the range of -0.55 Vdc and
-0.85 Vdc, and the voltage at
should fall in the range
of 0.55 Vdc to 0.85 Vdc. If either of the voltages at
and
do not fall within these ranges,
change
the value
of factory-select component
Decreasing the value
of
decreases the magnitude of the voltages at both
and
Conversely, an increasing the value
of
increases the magnitude of the voltages at both
and
Refer to
3-3 for the acceptable
range of values for
and to
3-4 for HP part numbers.
Refer to Figure 3-82 for the location of
For example, if the voltage measured at
is -0.87 Vdc and
the voltage measured at
is 0.86 Vdc, then the absolute
value of the resulting sum is -0.87 + 0.86 = 0.01 Vdc. Since the
resulting sum is less than 0.20 Vdc, the
Sampler is probably
not faulty. For this example, the value of
should be
reduced to decrease the magnitude of both measured voltages to
within the recommended ranges. The magnitudes of the voltages
measured at
and
are:
Voltage at
= -0.87 = 0.87 Vdc
Voltage at
= 0.86 = 0.86 Vdc
10. Verify that the loaded value of factory-select resistor
is
ohms.
Refer to Figure 3-82 for the location of
Factory-select resistor
must be loaded with a value of
ohms for proper operation of the HET UNLOCK Detector circuit
in HP 85660B RF Sections
Phase Lock Assembly HP Part
Number 85660-60226 and 85660-60256).
must be loaded
with a value of
ohms for use in HP 85660A RF Sections.
11. Set the spectrum analyzer LINE switch to STANDBY.
3-162 Adjustments
