Korg EX-800 Service Manual page 20

4.
Master oscillator
check and
adjustment:
6.
Resonance check and adjustment:
Set
tune knob to
center and bend
intensity
to
maximum.
1) Select program no.
14.
Connect
AT-12
to
line out
jack.
1)
Select
program no. 12.
2)
Depress
C3 key
of
POLY-800.
2l
Play C3 key of
POLY-800.
3)
Confirm that waveform
is
as
shown in figure
2.
4) Adjust VR5
if
necessary
to
prevent
oscillation or
to
cor-
3) Confirm
AT-12
indication
of
-
1
OCT, C,
0 cent.
lf
nec-
rect waveform deviation
f
rom figure
2 example.
essary,
adjust by turning KL-003 coil.
4) Next, push
joystick to
maximum upward
pitch
bend
position and
confirm AT-12
reading
of
-
1 OCT,
G, +35
cents.
Adjust
KLM-601
VR2
if
necessary.
5)
At
maximum
joystick
downward
pitch
bend
AT-12 indi-
cation should
be
-2 OCT,
F,
-35
cents.
Adjust
KLM-601
VR
1
if
necessary.
VR3
is a semi-fixed resistor
to
fix
range
of tune VR
on
front
panel.
Confirm +40
-
+70
cents
when tune
VR
is
at #
max
position.
Confirm
-4O
-
-70
cents
when
tune VR is at b
max
position.
Fig.2
lf
necessary,
Adjust VR3.
5.
Cutoff
check and adjustment:
1)
Select program
No.
13.
2l
Plav C3 key
of
POLY.800
3)
Connect oscilloscope
to
CNOA
pin
1 and
observe
wave-
form
as
in figure
1.
4)
Adjust VR2
to
obtain maximum waveform amplitude.
MAX AMP LEVEL
Fis.
1
1.5msec
lt2OoÄl
-t
F-
0.3Vp-p
(t2Oo/.1
0.1V/div,
l msec/div
-18-