OB-SX internal power supply for MIDIcontrol


This Interface needs 5V 100mA DC Power.
To supply the MIDIcontrol interface from your OBSX, please follow figure 1..3:

before you go ahead, please make sure your OBSX has the Oberheim 1458B board, with identical traces as shown below.
some very old of the gray cover OBSX have different boards.
If the trace to cut is missin on your board, you can't do this modification.

But most OBSX can be modified easily this way:


1. Cut trace below U67 as shown in figure 1 & 2
2. SolderĀ  a 10 OHM resistor from U67 Pin16 to the through hole solder point below the trace cut as shown in figure 3.

 

Figure 1 Figure 2 Figure 3
beforeCutTrace afterCutTrace 10OhmsBridge