3. IF
Bandpass
Adjustment
Procedure
1. Set the HP 8560A
m
switch off and disconnect the power cord. Remove the analyzer
cover and fold down the A2 Controller, A3 Interface, A4 Log Amp, and A5 IF assemblies.
Reconnect the power cord and set the (LINE) switch on.
Allow the analyzer to warm up for
at least 30 minutes.
2. Connect the negative DVM lead to pin 6 of A5J6. See Figure 2-5. Set the HP 3456A
controls as follows:
FUNCTION
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DC VOLTS
RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lOV
3. On the HP 8560A press (PRESET) (SPAN) 2
INIHz)
LCAL)
and IF ADJ OFF.
LC Bandpass Adjustments
4. On the HP 8560A, press ADJ
CURR
IF STATE. Wait for the IF ADJUST STATUS message
to disappear before continuing with the next step.
5. Read the voltage on
A5TP5
(th
is is an empty-hole type of test point). If the voltage is
less than
+6.06
Vdc, turn A5L300 LC CTR 1 clockwise. If the voltage is greater than
t6.26
Vdc, turn LC CTR 1 counterclockwise.
6. Repeat steps 4 and 5 until the voltage reads
t6.16
Vdc
flO0
mV.
Note
If the range for the LC CTR adjustment is insufficient, replace the
appropriate factory-selected capacitor as listed in Table 2-6. To determine
the correct replacement value, center the LC CTR adjustment and press
ADJ CURR IF STATE. After the IF ADJUST STATUS message disappears, read
the DVM display. Choose a capacitor value from Table 2-7, based on the
DVM reading and the presently loaded capacitor value. Table 2-10 lists a few
capacitor part numbers.
Caution
Set the HP 8560A
m
switch off before removing or replacing any shield.
7. Move the positive DVM lead to
A5TP6.
8. Adjust
A5L301
LC CTR 2 by repeating steps 4 through 6.
9. Move the positive DVM test lead to
A5TPl
(this is a resistor-lead type of test point).
10. Adjust A5L700 LC CTR 3 by repeating steps 4 through 6.
11. Move the positive DVM test lead to
A5TP2
(this is a resistor-lead type of test point).
12. Adjust A5L702 LC CTR 4 using the procedure in steps 4 through 6.
Adjustment Procedures 2-21
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