Akai AX80 Service Manual page 13

3)
Turn
off
the
Memory
Protect
SW.
4)
Save the
above parameters
to
one
of
Memory Bank
(e.g.
Bl)
and
turn
ON
the
Memory
Protect
SW.
5)
Select
any
Memory
Bank
or
Preset.
Do
not touch
any
keys.
6)
Select the
Memory
Bank
again
where
the
above
par-
ameters
are
saved
(e.g.
Bl).
7)
Connect
the oscilloscope
probe
to
IC
101
Pin
1.
8)
Set the oscilloscope
range
so that the
waveform
can
be seen
clearly.
9)
Press
one-octave lower
C
key (C5) from
the highest
C
key (C6)
as the
1st
key
to press.
10)
Check
peak-to-peak
voltage
of
the
waveform.
2V
Ei
....
V
\
\
\
V
S£
T
I
>
\
N
\
\
\
If
\
V
Jl
^1
Fig.
7-2 Output waveform
when C5
is
depressed.
1
1)
Connect
the oscilloscope probe
to
Pin
1
of
the
fol-
lowing ICs and
read peak-to-peak
voltages.
Key
No. ICNo.
2nd
key
D5
IC201
3rd key E5 IC301
4th key F5 IC401
5th
key
G5
IC501
6th
key
A5
IC601
7th
key
B5
IC701
8th
key
C6
IC801
* Key
numbers
are indicated as the
FREQ
RANGE
at
"16"
setting
(See
Fig. 4-1).
'PICAU
Fig.
7-3 Output waveform when C6
is
depressed.
12)
Determine
the
average peak-to-peak
voltage
(i.e.
lOVp-p) from above
readings.
13)
Connect
the oscilloscope
probe
to
IC101 Pin
1.
14)
Press the lowest
C
key (CI)
and
read peak-to-peak
voltage,
then change
the
connection
to
IC201
pin
1,
press the
next higher key (Dl)
and
read
Peak
to
Peak
voltage in the
same manner
as the
item
1 1)
above.
1
5)
Find the lowest Peak-to-peak voltage
and
adjust
by
turning
VR1
to that so that this
lowest peak-to-peak
voltage
on
this particular
voice
will
be the
same
as
the average peak-to-peak voltage
from
the
item
12.
Fig.
7-4
Output waveform
of lowest
Peak-to-Peak
voltage
16) If
you can
not
go back
to this
voice
number,
simply
switch to the other
Memory
Bank
then
back
to the
same bank
as the item 6
(e.g.
Bl).
17)
Press the lowest
C
key
(CI) as the
1st
key then next
higher
key
until
you
get
the voice
you
want.
18)
Adjust
VR1
as
same manner
as
the item
15.
12
SERVICE
MANUAL
AX80