IDC Header Tester Two Board version

Eurorack modular synthesizers use IDC connectors to distribute power. They are 16 pin 2x8 male headers, or 10 pin 2x5. In each case, there are two columns of pins, #1 on the right, with 3, 5, 7, ... above it, and 2, 4, 6, 8, ... on the left.

Pins 1 & 2 are shorted together to supply -12V; pins 3, 4, 5, 6, 7, 8 supply GND; pins 9 & 10 provide +12V. Some companies only use these 10 connectors. On a 16 pin version, pins 11 & 12 provide +5V, and the remainder are used for a control voltage and a gate. The +5V can be useful, but the CV and gate not so much.

Female connectors are pressed on to ribbon cable to mate with the male headers. I wanted a way to test cables and power distribution bars, to ensure the correct wires are connected, and no unintended shorts have occurred.