Yamaha CS-30 Service Manual page 32

CS-30(S/S 1001-)
VCA Circuit Board
1. Voltage Control Amplifier Circuit No. 1 (VCA1)
a. Set the VCF1 (PVR1), VCF2 (PVR2), /V VC01 (PVR3) and MOD DEPTH (PVR4) to 0, and set
the HOLD/EG switch (PSW5) to HOLD.
Adjust (VR i) , when (VR
2
) is at approximately its center position, so that +3
±
0.1V is present at
TP1.
Then set each of the EG1 ~~ 3 sliders to either 0 or S and adjust VR
2
) so that —200 ± lOmV is
present at TP1 when the HOLD/EG switch (PSW5) is set to EG (i.e., when OV input is present at the
third pin of ICi).
After the above adjustments, set the HP/BP/LP switch (PSW2) to HP, the MOD FUNCTION (PSW7)
to /V and VCF2 (PVR2) to 10.
b. As in 1—(a), set the HOLD/EG switch (PSW5) to HOLD and the VC02 FEET to 4'. Adjust the CUT
OFF FREQ of VCF2 and the RESONANCE so that a 1053Hz, 3Vp-p waveform is input to the HP2
(®-11 > terminal when the C4 key is ON.
At this time adjust (VR 31 so that a 1.3Vp-p waveform is present at TP2.
Next set VCF2 (PVR2) to 0, MOD DEPTH (PVR4) to 10 and LFO SPEED to F. Adjust (VR
4
] so
that the TP2 output waveform level is minimum when a 100Hz, 3Vp-p wave is added to the
f\J
((2)—2) terminal.
2. Voltage Control Amplifier Circuit No. 2 (VCA2)
a. Set the MOD DEPTH (PVR5) to 0, MOD FUNCTION (PSW8) to
f\/
and the HOLD/EG switch
(PSW6) to HOLD.
When (VR 6) is set to approximately its middle position, adjust [VR 5; so that +3 ± 0.1V is present
at TP3.
Then set each of the EG1 ~ 3 sliders to either 0 or S and adjust VR6 so that —200 ± lOmV is
present at TP3 when the HOLD/EG switch (PSW6) is set to EG (i.e., when 0V input is present at the
third pin of
IC
3
).
b. As in 2—(a), set the HOLD/EG switch (PSW
6
) to HOLD, VC02 FEET to 4' and switch the C
4
key
ON. Adjust the VC02 CUT OFF FREQ and RESONANCE so that a 1053Hz, 3Vp-p waveform is
present as input at the HP2 (®-11) terminal. Set the RMO volume (PVR
6
) to NORMAL. At this
time a 6.6 ± 0.3V waveform should appear at TP5.
With everything set in this condition, adjust [VR 7] so that a 1.5 ± 0.05V waveform is present at TP4.
Next set the VC02 section KBD/SEQ switch to SEQ and turn the SEQ section PITCH 1 all the way
to the left (so that 0V appears at the HP2 (J)-11) terminal). Also set the LFO SPEED to F. Adjust
(VR 8) so that the TP4 output waveform is minimum when a 100Hz, 3V A7 waveform is added to
the
f\J
((
2
)—2) terminal.
-30-