Korg POLYSIX Service Manual

8.
ADJUSTMENT
PROCEDURE
Caution:
This
unit has
been precisely
adjusted
Bt
the
factory before
shipment.
Therefore, absolutely do not
turn
any of
the
variable resistors
other than
those
required for
servicing. Testing
and
adjustment
should
be
performed
only after
allowing
the
unit to warm up
for
ten minutes. Variable
resistor
locations
are marked on separate charts.
*
The
following
are required
for the test
procedures:
Digital
voltmeter
(DVM)
4-1/2
digit
Oscilloscope
Tuner
Korg
WT-1
2,
etc.
Audio amp
and speaker,
or
headphones.
1.
Please
check the
following
before
proceeding.
1)
Check
all
connections to
make
sure
they are
correct
and
secure.
2)
Check
memory back-up
battery
voltage. KLM-367
circuit
board
battery voltage
should
be
3.60V
4.10V,
2.
Power
supply check
and adjustment
(KLM-376).
Use
a
DVM
to check the
following
test
point
(TP)
voltages.
(Obtain
ground
in
front of
LED.):
1)
+15V
for
TP-J7, Adjust VR3 to
obtain
+15.000V
±50mV.
2)
-15V
for
the
right side
of TP-R18.
Confirm
-15.000
mV
±300mV.
3)
+5V
for TP-J2.
Adjust
VR2 to
obtain
+5,000
±10mV.
4)
-5V
for TP-J1
.Adjust VR1 to
obtain
-5.000V
±10mV.
3.
KLM-367
check
and
adjustment.
(1)
Reset
circuit.
With
controls at
the
normal
setting
(fig.
1),
connect a
dummy
56kohm
2P (2-pin)
connector
to
the KLM-376
2P
plug
(male). If
connector
not
available
attach 56K
resister
with
small test
clips
(E-Z-Hook
or
Similar)
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EFFECTS
Fig.
1
Normal
setting.
1)
Turning
VR1
from the
counterclockwise
position
towards
the
clockwise
direction,
adjust
so
that
the
BANK
A~D,
MANUAL,
TAPE
ENABLE,
and
PROGRAM
1
~
8
LEDs
all light up
(instead
of
only
BANK A
and
PROGRAM 1).
2)
Confirm
that
only
the BANK
A and
PROGRAM
1
LEDs
light up
when
you
remove the
56kohm
2P
connector.
(2)
D/A
adjustment.
1)
Set
MANUAL
to ON,
CUTOFF
to
10,
and
EFFECT
INTENSITY
toO.
2)
Set circuit
board SW1
to
TEST
position.
3)
Confirm
that
PROGRAM
LEDs
1
&
8 alone
light
up
when the
TAPE SW is
switched
back
and forth
from
DISABLE
to
ENABLE
and back to
DISABLE.
4)
If
LEDs
other
than
1
and 8
light up,
adjust VR6
(offset) and
VR7
(width)
so
that only
1 &
8
light
up.
5)
Turning
VR7
clockwise, adjust so
that
the
lit
LEDs
shift to
1 &
8.
In the
shift from
2
& 7
to 1
& 8
there may
be
some
time lag
between
the two.
If
this
is
very large,
adjust VR6 to
minimize it.
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7
8
6)
Switch
the
circuit
board
SW1
to
the
NORMAL
position.
Confirm that
LEDs 1 & 8
remain
lit up
without
any change.
7)
Confirm
that output
DC
click
noise
is
within
6Vp-p
when
power
is
switched
off.
8)
Turn
power on and
confirm that
the
BANK
A
Bnd
PROGRAM
1 LEDs
light up.

Korg POLYSIX Specifications

General

Type	Analog
Polyphony	6 voices
Oscillators	1 VCO per voice
Effects	Chorus, Phaser, Ensemble
Keyboard	61 keys
Memory	32 patches
Year Released	1981
Waveforms	Sawtooth, Pulse
Filter	24dB/octave Low Pass Filter
LFO	Triangle