Guide On Engineering Changes - Roland SH-2000 Manual

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. VC0-2
IT132 is used in place of µPA41C formerly used . .
These are interchangeable each other..
2. OP-12
OP-12C is used in place of OP-12B. The difference is
that R575, 47KS1 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 100KS1 from 33KS1. When replacing the
F ET'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
SERIAL NO.
VCF-2-+ VCF-2A
*Interchangeable . . Value of R819 on MX-1
differs for each . . See Circuit Diagram. Tone
differs slightly . .
PS-14C-+ PS-14C-D
PS-21C-+ PS-21C-D
*Interchangeable . .
578049
578050
608899
608900
4. AR-2, VG-7, MX-1
For increased reliability, FET's 2SK44 C and 2SK44
D are changed to 2SK30A 0 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
IC 830C used on PS-14C is no longer available . .
Instead µA78M15UC is used on PS-14C-D of present
products. In conjunction with this change, R601 and
R602 are changed to 33S1 from 1 OOS1 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.
OP-12
VC0-2
VCF-2
I
PS-14C
I
B
G
PS-21C
MX-1
OP-12
VC0-2
VCF-2A
I
PS-14C
I
B
G
PS-21C
MX-1
OP-12
VC0-2
1
VCF-2A
IPS-14C-DI
B G
PS-21C-D
MX-1
.·
1
!@Roland