ADJUSTMENTS

5-21.BANDWIDTH FILTER ADJUSTMENTS(SERIAL PREFIX 1909A)(Cont'd)

11.Set FREQ SPAN/DIV to 20 kHz, RESOLUTIONBW to 30 kHz,and SWEEP TIME/DIV to 10 mSEC.

NOTE

A non-metallic tuning tool is required for adjustments on Bandwidth Filter Assemblies A11 and A13.

12.Connect crystal shorts (through cover access holes) across A13TPWTP2, A1lTPl/TP2, and A11TP4/ TP5.

NOTE

Keep crystal spike centered during adjustments. The SYM and CTR adjustments for eachcrystal are interacting.

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

CHECK CENTERING

HERE (SPIKE IS

CRYSTAL RINGING)

CHECK SYMMETRY

HERE (LOW ON SKIRTS)

FIGURE57. ADJUSTING CRYSTALSYMMETRY ANDCRYSTALCENTERING

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

15.Remove crystal short from A13TPl/TP2.