Service manual

4.3.5 FILTER CONTOUR ATTACK AND DECAY TIMES
a) Depress 1OCT tab switch.
b) Depress MUTE (BRASS MUTE, Satellite) tab
switch and observe filter contour at the source of Q20
(Figure 4-3) while repeatedly striking C key one
octave from bottom of keyboard.
c) Adjust filter decay and attack trimpots R98
and R105 until the filter contour matches the pattern
shown in Figure 4-8.
NOTE
It may prove convenient to externally trigger
the oscilloscope from the bottom of R64
for paragraphs 4.3.5 through 4.3.7.
~ +1.7V-
ov-
-0.5V-
R105
ATTACK
R98
DECAY
200 MSEC ' 200 MSEC
FIGURE 4-8 FIL TER CONTOUR A T Q20 SOURCE
4.3.6 LOUDNESS CONTOUR ATTACK TIME
a) Observe waveform at junction of R165 and
R166 (Figure 4-3) with MUTE (BRASS MUTE,
Satellite) and 1 OCT tab switches still down.
b) Depress C key one octave up from bottom of
keyboard and adjust amplitude attack trimpot R174
to match the attack contour shown in Figure 4-9.
+3.7V.
KEY DOWN-*
0V-
^60-70.
MSEC
-20 MSEC
FIGURE 4-9 LOUDNESS ATTACK A T JUNCTION
OF R165 AND R166
4.3.7 LOUDNESS CONTOUR DECAY TIME
a) Lift MUTE (BRASS MUTE, Satellite) tab
switch and depress PIANO (STRING STRIKE,
Satellite) tab switch.
b) Assure 1 OCT tab switch is still down and
depress C key one octave up from bottom of keyboard.
c) Observe waveform at junction of R165 and
R166 (Figure 4-3) and adjust amplitude decay
trimpot R190 for the decay contour shown in
Figure 4-10.
J
FIGURE 4-JO LOUDNESS DECA Y ATJUNCTION
OF R165 AND R166
4.3.8 VOLTAGE CONTROLLED AMPLIFIER BALANCE
a) Lift PIANO (STRING STRIKE, Satellite)
tab switch and short junction of R149 and C30
(Figure 4-3) to ground.
b) Set VOLUME slide control at maximum and
connect oscilloscope probe to top of R162.
c) Hit and release a key and adjust VCA balance
trimpot R160 until a minimum click or thump is
heard and step waveform at top of R162 does not
exceed lOmv.
4.3.9 VIBRATO DEPTH
a) Set vibrato depth trimpot Rl fully CCW.
I
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