The Lighting Controller

I am trying to get an old lighting rig working at work, as the old mixing deck (installed in the 70s) is dead. I think everything is made by Colourtran or something.

Anyway, I can get our USB-to-DMX to control the new led lighting units we have, but I would really like it to work with the old dimmer boxes (where the par cans plug into). This was controlled by the 5-pin deck that is now dead. I have bought a 3-pin to 5-pin coupler from eBay to see if that works, but it doesn't. How could I get this USB device to control the dimer box from the software?

First you must be sure your dimmer packs are DMX 512 control and not some proprietary or analog control. One way to tell is if the dimmer pack has DMX address dip switch. If so just add it in setup and configure its starting channel. Open the device in editor, turn on DMX output and move the faders for the appropiate channels. Also, sometimes DMX cables require pins 2&3 be swapped for older devices.