3. IF Bandpass Adjustment

Table 2-6. Factory-Selected LC Filter Capacitors

1CC CTR Adjustment Fixed Factory Select Capacitor

A5L300 LC CTR 1

A5C326

A5L301 LC CTR 2

A5C327

A5L700 LC CTR

3

A5C717

A5L702 LC CTR

4

A5C718

Table 2-7. LC Factory-Selected Capacitor Selection

DVM Reading (V)

 

Currentl! Y Loaded CaDacitor Value (pF)

 

 

 

Replace

Replace

 

Replace

 

Replace

 

Replace

Replace

 

6.8

with:

8.2 with:

 

10 with:

 

12 with: I15 with:

18 with:

0 to 1.5

*

*

 

*

 

*

 

*

*

 

 

*

*

*

 

1.5 to 2.5

18

18

*

 

 

 

 

*

*

2.5

to 3.5

15

15

18

18

 

 

*

3.5

to 4.5

10

12

15

15

18

*

4.5

to 5.5

8.2

10

12

15

18

 

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

*

6.8

8.2

10

12

15

 

8.5 to 9.5

*

*

6.8

8.2

12

15

*

*

9.5 to 10

6.8

8.2

10

12

 

 

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

XTAL Bandpass Adjustments

13.On the HP 856OA, press @ii) 1 m and ICAL).

14.Move the positive DVM test lead to A5TP7.

15.On the HP 8560A, press ADJ CURR IF STATE. Wait for the IF ADJUST STATUS message to disappear before continuing to the next step.

16.Read the voltage displayed on the DVM. If the voltage is less than t6.06 Vdc, turn A5T200 XTAL CTR 1 clockwise. If the voltage is greater than t6.26 Vdc, turn XTAL CTR 1 counterclockwise.

17.Repeat steps 15 and 16 until the voltage reads t6.16 Vdc flO0 mV.

2-22 Adjustment Procedures