Korg DW-6000 - D;A Converter Voltage Check; DWGS Clock Check; OSC1 VCA Level Check

Use the
settings
listed below
for the check and
adjustment
procedures.
For convenience,
save these
settings
on
tape
so that
they
can be
loaded
quickly
the
next time
DW-6000
servicing
is
required.
RESET
SWITCH
Fig-1
You
should
have received
the
DW-6000 voice
display
card
by separate
mail.
This
is
used
to
show which
voice
is
operating
when
keys are
played
on the
keyboard.
(See
figure
1
.)
Turn
off the
power
on
the
DW-6000
and
connect
the
card's
1C
clip
to
IC7
(40H374)
on the
KLM-653
board.
Be
sure
that
the
“1"
marked
on
the clip
is at the
IC7
number
1
pin
side.
If
the
DW-6000
or
the
voice
display
card
starts
behaving
erratically,
reset
the
card
by
pressing
its reset
button.
(And
reset
the
DW-6000
by turning
its
power off
and
on
again.)
Be
sure
to
turn off
the
power
on
the
DW-6000
before
removing
the
voice
display
card.
1.
D/A
converter
(DAC)
reference
voltage
check
and
adjustment.
(KLM-654)
1)
.
Connect
a
digital
voltmeter
(DVM)
to the
KLM-654
D/A check
point
(or
IC1
[4558]
7
pin)
(connect
ground
to
C31
GND
side),
confirm
a
reading
in
the
range
of
1.995V
~2.005V.
2)
Adjust
VR2
if
necessary
to
obtain
a
value
that
meets
the above
specification.
ground
side).
Confirm
a
DWGS
clock
frequency
within
the
range of 6,395kHz~6,405kHz.
2)
Adjust
VR1
if
necessary.
3.
OSC1 (oscillator
1)
VCA level
check and
adjustment
(KLM-655)
1)
Connect
an
oscilloscope
to the
KLM-655
test
point
(ground
goes to
C6 GND
side).
2)
Select
program
number
1
1
.
3)
Play
key
C3
and
confirm
a
waveform
level
of 0.5V
p-p
(±20mV
p-p)
(fig-2).
0.5V
±
20mV
Fig-2
4)
Check
all six voices
in the
same
way.
5)
If
a voice does not
meet
the
level
specification,
adjust
it by
turning
its VCA
adjustment
VR:
No.
2,
7,
12,
17,22,
or 27.
2.
DWGS
Clock
check
and
adjustment.
(KLM-654)
1
)
Connect
a
frequency
counter
to
the
clock
adjustment
test
point
or
IC45
(LS04)
6-pin
(ground
goes
to C104
—
30
—