3. IF Bandpass Adjustment

 

 

Note

If the range for the XTAL CTR adjustment is insufficient, replace the

 

appropriate factory-selected capacitor as listed in Table 2-8. To determine

 

the correct replacement value, center the XTAL 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 2-9, 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 luNE) switch off before removing or replacing any shield.

18.Move the positive DVM test lead to A5TP8.

19.Adjust A5T202 XTAL CTR 2 using the procedure in steps 15 through 17.

20.Move the positive DVM test lead to A5TP3.

21.Adjust A5T500 XTAL CTR 3 using the procedure in steps 15 through 17.

22.Move the positive DVM test lead to A5TP4.

23.Adjust A5T502 XTAL CTR 4 using the procedure in steps 15 through 17.

Table 2-8. Factory-Selected XTAL Filter Capacitors

XTAL CTR Adjustment Fixed Factory Select Capacitor

A5T200 XTAL CTR 1

A5C204

A5T202 XTAL CTR 2

A5C216

A5T500

XTAL CTR

3

A5C505

A5T502

XTAL CTR

4

A5C516

Table 2-9. XTAL Factory-Selected Capacitor Selection

DVM Reading (V)Currently Loaded Capacitor Value (pF)

 

 

Replace

Replace

Replace

Replace

Replace

Replace

 

 

15 with:

18 with:

20 with:

22 with:

24 with:

27 with:

0 to 1.5

*

*

*

*

*

*

 

 

 

 

 

 

1.5

to 2.5

27

*

*

*

*

*

2.5

to 3.5

22

27

27

*

*

*

3.5

to 4.5

18

22

24

27

27

*

4.5 to 5.5

18

20

22

24

27

*

5.5to 6.5 no change no change no change no change no change no change

6.5to 7.5 no change no change no change no change no change no change

7.5 to

8.5

*

15

18

18

22

24

8.5 to

9.5

*

15

15

18

20

24

9.5 to 10

*

*

15

18

20

24

* Indicates a condition that should not exist; suspect broken hardware.

Adjustment Procedures 2-23