ADJUSTMENTS

MODEL8559A

ADJUSTMENTS

5-21. BANDWIDTH FILTER ADJUSTMENTS(Cont'd)

LC Alignment

Accidentally shorting the case of A9Q1 (directly below A9TP6) to ANY test point will cause catastrophic failure to Sweep Generator Assembly A9.

24.Set RESOLUTION BW control to 100 kHz. Jumper A9TP6 to A9TP8. This forces the BW7 line to

+15Y Set FREQ SPAN/DIV to 100 kHz.

NOTE

When Bandwidth Filter Assemblies A l l and A13 are installed with covers in place, midget copper alligator clips (HP Part Number1400-0483)can be used to short test points to the cover.

25.Perform preliminary LC filter adjustments as follows:

NOTE

It might be necessary to adjust the REF LEVEL FINEcontrol to obtain an on- screendisplay during the following adjustments.

Remove A! 3 cover and install A13 on extender board.

Short to ground the following test points: A13TP6, A11TP3, and A11TP6. (This widens all but one LC pole).

Center signal on CRT with TUNING control. Adjust A13C73 for minimum signal amplitude.

Disconnect short from A13TP6 and short to ground A13TP3.

Adjust A13C74 for minimum signal amplitude. Remove shorts from A13TP3, A1 lTP3, and A11TP6.

Reinstall A13 and cover. Short A13TP3 and A13TP6 to ground. Remove A11 cover and install A l l on extender board.

Short A11TP6to ground.

Adjust A11C73for minimum signal amplitude.

Disconnect short from A11TP6and short to ground A1lTP3.

Adjust A1 1C74for minimum signal amplitude.

Disconnect shorts from test points and reinstall A11and cover. Leave jumper from A9TP6 to A9TP8 in place.