Roland SH-2000 Service Notes page 4

NOV
10 1977
SH-2000
GUIDE
ON ENGINEERING
CHANGES
Details
of
engineering
changes
are described
in
each
section
concerned.
The
gist
of them
are
summarized here
for
quick comprehension.
1.
VCO-2
IT132
is
used
in
place of
/xPA41C
formerly used.
These
are
interchangeable each
other.
2.
OP-12
OP-12C
is
used
in
place of
OP-12B. The
difference
is
that
R575, 47KJ2 on
foil
side
of
OP-12B
is
brought
onto
parts side
on OP-12C. Therefore, the
foil
pattern
differs slightly
each other
The two PCB's
are per-
fectly
interchangeable.
Also,
in
recent products,
2SK30A
GR's
are
used
in
stead of
2SK30A
Y
in
hold circuit
of older products.
In
conjunction with
this
change,
R513
and
R514
are
changed
to
100K12 from 33KJ2.
When
replacing the
FET's,
change the
resistors,
too.
This
change
has
been
made
with
a
view to reducing the
leakage
voltage.
3.
MOUNTING SCREW
In
order
to increase
structural strength,
two mounting
screws
are
added
in
recent products.
One
is
to secure: control unit
(left)
to side
board.
The
other
is
to secure:
keyboard
chassis (right)
to
side
board.
CHANGES
OF
PCB's
4.
AR-2, VG-7,
MX-1
For
increased reliability,
FET's
2SK44 C
and
2SK44
D
are
changed
to
2SK30A O
and
2SK30A
Y
respec-
tively,
on PCB's
AR-2,
VG-7
and
MX-1
of recent
products.
The FET's, accordingly the PCB's, are
inter-
changeable each
other.
5.
PS-14C
-
PS-14C-D
1C
830C
used
on PS-14C
is
no
longer available.
Instead
/.(A78M15UC
is
used
on PS-14C-D
of present
products.
In
conjunction with
this
change,
R601 and
R602
are
changed
to
33fi
from
100J2 of
PS-14C.
The two PCB's
are interchangeable.
Also, interchanging the
IC's
is
also possible
by taking
into
account
that:
1)
the pins are slightly
different,
and
2)
R601
and
R602
values are different.
SERIAL NO.
V
578049
VCF-2
^
VCF-2A
*
Interchangeable.
Value of
R819 on MX-1
differs
for each.
See Circuit
Diagram.
Tone
differs slightly.
578050
V
608899
PS-14C-^PS-14C-D
PS-21C^
PS-21
C-D
*
Interchangeable
608900
V
1
S
Roland