Chapter 2 71
Adjustment Procedures
3. IF Bandpass Adjustment
Equipment
Digital voltmeter .............................................................HP3456A
DVM test leads ..............................................................HP34118A
Special tuning tool (for slot-type tuning slugs) ............ 8710-1010
Special tuning tool (for fork-type tuning slugs) ........... 8710-0772
Procedure
1. Press LINE to turn the spectrum analyzer off and disconnect the
power cord. Remove the spectrum analyzer cover and fold down the
A2 controller, A3 interface, A4 log amp, and A5 IF assemblies.
Reconnect the power cord and press
LINE to turn the spectrum
analyzer on. Allow the spectrum analyzer to warm up for at least 30
minutes.
2. Connect the negative DVM lead to pin 6 of A5J6. See Figure 2-5 on
page 70. Set the HP 3456A controls as follows:
Function ...................................................................DCVOLTS
Range ..................................................................................10V
3. On the HP 8560E/EC, press
PRESET, SPAN, 2, MHz, CAL, and IF ADJ
OFF.
LC Bandpass Adjustments
4. On the HP 8560E/EC, 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 (this 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 +6.26 Vdc, turn LC CTR 1
counterclockwise.
6. Repeat steps 4 and 5 until the voltage reads +6.16 Vdc ±100 mV.
NOTE If the range for the LC CTR adjustment is insufficient, replace the
appropriate factory-selected capacitor as listed in Table 2-6 on page 72.
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 on page 72, based on the DVM reading
and the presently loaded capacitor value. Table 2-10 on page 74 lists a
few capacitor part numbers.
CAUTION Press LINE to turn the spectrum analyzer off before removing or
replacing any shield.
7. Move the positive DVM lead to A5TP6.
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