Service manual

14 Agilent 382A Operating and Service Manual
Operation
Setting The Dial The dial will need resetting if a new dial is installed, if the stops have been
forced hard, or if the dial has slipped. To reset the dial connect as in Figure3
on page11 and proceed as follows:
1. Set signal source to lowest point of 382A frequency range. Adjust the
output RF signal for 1000 Hz square wave modulation.
2. Set 382A under test to dot which appears at approximately 47 dB on the
attenuator dial. Adjust the 382A padding attenuator for a reference of 1
dB on the 50 dB range of the SWR meter.
3. Set 382A dial to dot which appears approximately the same distance on
the other side of the MAX indication. The SWR meter reading should
not have changed more than 0.2 dB.
NOTE If a double peak in maximum attenuation occurs, the resistive center card
has been installed with the emulsion side reversed. Refer to the replacement
procedure for correct installation procedure.
4. If adjustment is necessary, loosen the setscrews and the dial hub
clamping screw (see Figure5 on page13) in the dial hub. Adjust the dial
so the difference in power level between the two dots is 0. 2 dB or less
as indicated on the SWR meter. This aligns the dial to the angular
position of the center section. Tighten cap screw, Allen setscrews, and
recheck.