HP 8566B Adjustment Manual page 302

18. RF Module Phase Lock Adjustments
3-162 Adjustments
6. Connect the DVM to A6A9AlE5, and connect the DVM ground to
the metal case/shield of the A6A9 Phase Lock Assembly. Refer to
Figure 3-82 for the location of A6A9AlE5 and A6A9AlE6.
7. Note the DVM indication at A6A9AlE5.
8. Connect the DVM to A6A9AlE6, and note the DVM indication.
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 A6A9Ul Sampler or related circuit
components.
The voltage at A6A9AlE5 should fall in the range of -0.55 Vdc and
-0.85 Vdc, and the voltage at A6A9AlE6 should fall in the range
of 0.55 Vdc to 0.85 Vdc. If either of the voltages at A6A9AlE5
and A6A9AlE6 do not fall within these ranges,
of factory-select component A6A9AlR5. Decreasing the value
of A6A9AlR5 decreases the magnitude of the voltages at both
of A6A9AlR5 increases the magnitude of the voltages at both
range of values for A6A9AlR5, and to Table 3-4 for HP part numbers.
Refer to Figure 3-82 for the location of A6A9AlR5.
For example, if the voltage measured at A6A9AlE5 is -0.87 Vdc and
the voltage measured at A6A9AlE6 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 A6A9Ul Sampler is probably
not faulty. For this example, the value of A6A9AlR5 should be
reduced to decrease the magnitude of both measured voltages to
within the recommended ranges. The magnitudes of the voltages
measured at A6A9AlE5 and A6A9AlE6 are:
Voltage at A6A9AlE5 = -0.87 = 0.87 Vdc
Voltage at A6A9AlE6 = 0.86 = 0.86 Vdc
10. Verify that the loaded value of factory-select resistor A6A9AlR27
is 56.2K ohms. Refer to Figure 3-82 for the location of
Factory-select resistor A6A9AlR27 must be loaded with a value of
in HP 85660B RF Sections (A6A9 Phase Lock Assembly HP Part
Number 85660-60226 and 85660-60256). A6A9AlR27 must be loaded
with a value of 10K ohms for use in HP 85660A RF Sections.
11. Set the spectrum analyzer LINE switch to STANDBY.
Voltage at A6A9AlE5:
Voltage at A6A9AlE6:
change the value
Vdc
Vdc