Adjustment Procedures - Roland sh-101 Service Manual

NOV.Ist, 1982 SH-101
ADJUSTMENT PROCEDURES
(D)
PulseWidth
Set the
WAVEFORM
to
rU_
Adjust
VR-2 {D/A
TUNE)
until
the mark/space
ratio
is
1:1.
2.
VCO ADJUSTMENT
Precautions:
The
order of the
adjustment procedures
in
these adjustment specifications
were determined assuming that the
SH-101
unit
has not been
adjusted at
all.
Therefore,
when
only a
few
sections are to
be adjusted, please keep the
following points
in
mind.
•
When
adjusting the
VCO
Width,
VCO
Tune, and/or
VCF, be sure that the
D/A Converter adjustment
has
first
been completed. (This
is
because
D/A
Converter
failure
may
affect these
circuits.)
•
Because the
VCO
Width and the
VCO
Tune
interact
with each other, be
sure to
perform both adjustments.
1
.
2
.
Preparations:
•
If
the unit
is
in
the Test
mode,
release the
mode
by either pressing the
HOLD
button or resetting the
Power Switch
to
On.
• Set the panel controls asshown
in Fig.
1
.
• Connect the oscilloscope
to
SH-101
OUTPUT. Supply
the reference F
note (based on
A
= 442Hz)
to the
scope EXT. Input
for
the Lissajous
figure.
3.
VCF
ADJUSTMENT
Preparations:
• Set the panel controls as shown
in Fig. 2.
• Connect the oscilloscope to the
SH-101
OUTPUT.
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Keyboard
of the
SH-101
When
the
VCO
Range
is set
to 8'and the Transpose
5V switch to
MIDDLE, A4
corresponds
to
442Hz.
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Fig.
1
F4A4 F5A5
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1 .
Hold the
A4 key down, and
set
the
CUTOFF FREQ,
for
approximately
1kHz.
2.
Alternately, play the
F4 and F5
keys,
and
adjust
VR-8
(VCF
WIDTH)
until
the F5
figure cycle
Istwicethe F4 cycle.
1.
D/A
CONVERTER ADJUSTMENT
Note:
To compensate
for
the variations
of
the components, the
VCO
Tune
Circuit
is
designed so that a
+15V voltage can be supplied
or inhibited.
(The
position
is
shown
in
the circuit diagram with the
J
mark.)
If
the
adjustment cannot
be properly
performed by
adjusting
VR-7,
short-circuit
the break
in
the pattern on the back of resistor R102.
If
it
is
already bridged or wired,
open
it.
Preparations:
• Connect
the digital voltmeter (with
more
than
4
significant digits) to
the
CV OUT
jack.
• While pressing both the
LOAD
button and the
KEY
TRANSPOSE
button on the
SH-101
unit,
turn the Power Switch On. (The SH-101 unit
is
now
in
the
Test mode.)
4.
LFO
MOD
OFFSET
(A)
VCO
Width
Hold the F5 key
down,
and adjust either
VR-7 (VCO TUNE)
or
VR-9
(TUNE)
until the Lissajous figure
is
motionless.
Hold the F3 key down, and adjustVR-6
(VCO WIDTH)
until
the figure
is
again motionless.
The F5
pitch will
vary as
VR-6 (VCO WIDTH)
is
turned.
Repeat steps
1
and 2 until the
F3 and F5
figures are motionless.
Preparation:
• Connect
the digital volt-
meter
to test
points TP-1
and TP-2 on the
Bender
Circuit
Board
as
shown
in
Flg.3.
1.
Adjust
VR-3 (D/A LINE-
AR)
until
the voltmeter
reads 0
±
2mV
(A)
D/A Tune
Confirm that the
LOAD
and
TRANSPOSE LEDs
are illuminated.
If
any
of the
LEDs
other than the
LOAD
LED
is
illuminated, press the
LOAD
button.
Adjust
VR-2 (D/A TUNE) on the Synth.
Circuit
Board
until
the digital
voltmeter reads
OV ± ImV.
1
.
1
.
2
.
2
.
3.
(B)
D/A Width
(-f5V)
Press the
PLAY
button.
Adjust
VR-1
(-I-5V)
on the Synth. Circuit
Board
until
the digital volt-
meter
reads
2.75V ±
1
mV.
(B)
VCO
Tune
1.
Place the
unit in
the Test
mode.
(While pressing both the
LOAD
button
and the
KEY
TRANSPOSE
button.turn the Power Switch
On.)
2.
Press the
U & D button.
3.
Confirm that
VR-9 (TUNE)
issetirt the center position.
4.
Adjust VR-7 (VCO
TUNE)
until the
output value
is
442Hz.
1
.
2
.
Note:
The adjustment can be per-
formed from
the direction
of
the
foil
pattern.
(C)
D/A
Linearity
1
.
Press the
ARPEGGIO
DOWN
button.
2.
Adjust VR-3 (D/A
LINEAR)
on the Synth. Circuit
Board
until the digital
voltmeter reads 2.5
V ± ImV.
(C)
Range Width
Place the unit in
the Test
mode
Press the
U & D
button.
Press
the
UP
button, and adjustVR-5
(RANGE WIDTH)
until
the output
pitch
is
the
same
as the outputpitch
in
the
U & D mode.
1
.
2
.
(D)
Repeat the above procedures (A)
through
(C) until
all
the voltage read-
ings are within
±1
mV
of the specifications.
3.
4