ADJUSTMENTS

MODEL 8559A

ADJUSTMENTS

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

Center the signal with TUNING control. Using REF LEVEL FINE control, place signal peak a t 7.1 divisions (0.9 division from top graticule line).

Adjust A9R85 L C until signal is five divisions wide at the fifth graticule line (1 MHz wide at 3-dB points).

Set FREQ SPAN/DIV to 10 kHz and RESOLUTION BW t o 10 kHz.Center the signal with FINE TUNING control.Using REF LEVEL FINE control, place signal peak at 7.1 divisions.

Adjust A9R72 XTL until signal is one division wide at the fifth graticule line (10 kHz wide at 3-dB points).

Set FREQ SPAN/DIV to 20 kHz and RESOLUTION BW to 30 kHz.Center signal with TUNING control.Adjust REF LEVEL FINE control to place signal at sixth graticule line.

Remove top guide rail. Connect crystal shorts (through cover access holes) across the following pairs of test points: A13TPl/TP2, A1 1TPl/TP2, and A1 lTP4/TP5.

NOTE

Keep crystal spike centered during adjustments. The SYM and CTR adjustments for each crystal interact(the signal also drifts in this narrow span).

13.Adjust front-panel TUNING control to center bandpass spike (Figure 5-7) on the CRT display.

NOTE

A non-metallic tuning tool is required for adjustments on the A l l and A13 bandwidth filter assemblies.

14.Adjust A13C54 CTR for minimum signal amplitude. Then adjust A13C38 SYM and A13C54 CTR for a centered and symmetrical bandpass as shown in Figure 5-7.