Resonance Adjustment; Adsr Zero Adjustment; Vcf Octave Adjustment; Chorus Adjustment - Roland SH-3A Service Notes

(2) Adjust VR257(CLICK BIAS) so that no pulse waveform is seen on the
scope, repeating switch ON/OFF a key.
7-5. RESONANCE Adjustment
(1) Setting VCO all 0
CUTOFF FREQ 5
RESONANCE 8
Adjust VR256(RES SET) to get VCF oscillation, and then turn back
the VR until the oscillation may just go off.
7-6. ADSR ZERO Adjustment
(1) Adjust VR1O4(ADSR 0 ADJ.) to set the 20th terminal(0P-9A) voltage
at 0 volt.
7-7. VCF OCTAVE Adjustment
(1) Setting VCO all 0
CUTOFF FREQ 5
RESONANCE 10
(2) While depress F2 key and F3 key alternately, adjust VR255(VCF WIDTH)
to get one octave difference between F2 and F3.
( 3) Setting CUTOFF FREQ 0
Depressing the C4 key, adjust VR254( PREQ.ADJ.) to set its frequency
at 348Hz.
(4) Stepping (2) affects one octave difference between F2 and F3, so
repeat step (l) and (2).
7-8. CHORUS Adjustment
(1) Connect the scope to the 64th on 0P-10B.
(2) Setting 8* ON
VCO 81 Control 10
(3) While holding the Fl key down, adjust VR252(BIAS) so that the output
waveform looks like the figure.
(4) While holding the C4 key down, adjust
VR253(LINEARITY) as the same way as step (2).
(5) Connect the scope to the 66th on 0P-10B.
Setting CHORUS 2 - 3
20%
Adjust VR251(MOD DEPTH) so that the waveform seen on the scope may
be sailling and shuttling as shown in the figure.
However, the waveform height
shouldn't be less than 1/2
of Max.
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