Hammond Organ L-100 Series, Руководство по обслуживанию

Страница: 31 / 87

Page 31
oscilloscope’s VERTICAL INPUT to the disconnected brown
RCA plug.
b. Remove the black RCA cable from the BK (Black) RCA jack
located on the vibrato phase shift amplifier. Insert into the BK
RCA jack an adapter with two RCA jacks and one RCA plug.
Reconnect the RCA cable (black) into one of the adapter
RCA jacks and connect the oscilloscope’s EXT. TRIGGER IN
binding post to the remaining adapter RCA jack.
c. Set scope controls as follows:
1. TRIGGER: SOURCE-EXT., COUPLING-AC: SLOPE +
2. HORIZONTAL SWEEP 0.2 msec/cm.
3. VERTICAL SENSITIVITY 0.2 volt/cm.
d. Hold down key #7 (frequency #60) on the upper manual.
e. Adjust the TRIGGER LEVEL control for a stable pattern.
f. Adjust the VARIABLE sweep time control until one complete
sine wave covers 4 cm.
g. Adjust the VERTICAL VARIABLE control for a display height
of 4 cm.
h. Depress the VIBRATO NORMAL tab Adjust the VIBRATO
WIDTH control for a total phase shift swing of 2 cm (refer
to
Figure 4–1 . If VIBRATO WIDTH control does not give a
satisfactory result, select R133, Figure 5–2 between 220
Ω
and 1K
Ω
.
NOTE 4–5–A
Phase shift can be best read if waveform is centered so that the
center peak of the sine wave coincides with a graticule line.
Figure 4–1: Vibrato Adjustment Waveform
i. Release VIBRATO NORMAL tab. Single wave must be
centered ± ½ cm as shown in Figure 4–1 .
j. Disconnect external leads and adapter. Reconnect RCA
cables to proper jacks.
If an oscilloscope is not available, make the following listening test:
k. Depress FULL ORGAN tab. Hold down F, A, C chord near
center of the upper manual. Depress VIBRATO SMALL tab
and observe vibrato effect. Add VIBRATO NORMAL tab and