MD-1 Board B to Stops and Combination Button Cable C2

(This page last modified June 17, 2008)
 
 

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.