Yamaha CS-30 Service Manual page 38

CS-30(S/# 1001—)
4. Noise Generator Circuit
a. Adjust [VR
3
] to obtain 5± 1 Vp-p (2 dBm) output at terminal Nl (2 —1).
b. Adjust [VR 4] so that voltage fluctuates at terminal S/H LO—10) to an equal degree above and below
OV as the center, as illustrated below:
Terminal S/H (1-10)
Terminal
(10
-
mt
(With LFO speed at 50Hz)
5. EXT Pre-amplifier Circuit
a. Set FEET on VCOI to
8
',
S\J
VC01 on VCA1 to 10, and all others to 0, and turn EG/HOLD
selector switch to HOLD.
Then, set BALANCE on PN3 to 1 and adjust VOLUME to provide OUTPUT 1 with a 20mV (-40
dBm) output level when key C
4
is turned ON (1053Hz output).
Now, connect OUTPUT 1 to EXTERNAL-IN by using a guitar lead (20mV, 1053Hz is applied to
terminal ESI (£'-7).
b. After the completion of the setting mentioned in paragraph 5—a, 120mV output should be obtained
at terminal 0(
©-5)
when SIGNAL LEVEL (PVR4) is turned to 10. Also, 1.25V output should be
presented at terminal -20 I'D-3).
6
. EXT Trigger Circuit
In addition to the same setting as mentioned in paragraph 5—(a), set TRIGGER LEVEL (PVR3) to 10
and —20/0 selector switch on the rear panel to the 0 position. When SIGNAL LEVEL is set so that a
voltage of +60 ± 5mV is applied at terminal ETI (^—
6
), 0 ± 0.2V output should appear at terminal ETO
(@-5).
In addition, when SIGNAL LEVEL is set to 0, +15V output should be obtained at terminal ETO.
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