There are 48 stop switches and 11 combination buttons. They connect to MD-1 board B via two cables, one to P4 and one to P5, as follows:
Bass end
middle
treble end
____________________________________________________
NC 34 |
S T O P S W I T C H E S
|
|
|
Common bus 33-| 1 2
31 32 33 34
47 48 |
|____________________________________________________|
| |
| | | |
| |
| | (3 thru 30 | |
| |
| |
| | not shown) | |
| |
| |
32 --+ |
| | | |
| |
CABLE to P5 31 ----+
| | | |
| |
:
| | | | (19 thru
30 | |
2 ------------------+ |
| | not shown) | |
(stripe) 1 ---------------------+
| |
| |
\___________
| |
| |
/
NC 34
| |
| |
33 -------------------------------|-|-------------|--|--+
32 -------------------------------+ |
| | |
31 ---------------------------------+
| | |
CABLE to P4 :
| | |
18 -----------------------------------------------+ | |
17 --------------------------------------------------+ |
NC 16 through 12
|
11 --------------------------------------+
|
10 ------------------------------+
| +---+
:
| |
|
3 --------+
| |
|
2 -----+ | . . .
| |
|
1 --+ | |
| |
|
_|1_|2_|3____________________|10_____|11________|12_
| 1 2 3 4 5 6 7 8 9
10 CANCEL COMMON |
| C O M B I N A T I O N
B U T T O N S |
|
(below accomp. keyboard)
|
|____________________________________________________|
The above schematic is actually implemented like this:
P5 cable: directly to left 32 stop switches and common, as shown above.
P4 cable: wire 33 goes to stop switch common,
same as wire 33 of P5 cable.
wires 17 through 32 go to stop switches 33 through 48
wires 16 through 12 are cut short and are NC
wires 1 through 11 plus an extra 2 go to pins 1 through 13 of a 13-pin
IDC connector. One of the extra wires
- the one to pin 12 - is then connected to the common (ground) wire on
the stop switch rail.
The 12-wire cable from the combination buttons
go to a matching 13-pin IDC connector, pins 1 through 12. Pin 12 is the
common, and is thus connected to the stop switch rail. Pin 13 is not used
and has no wire to it.