I have an old Proto FA2, brown box, no circuit board, DCC plug, etc. I bought a Digitrax DH123 with no plug, just the decoder wires to wire the engine up. The only problem is I'm not real sure where all the wires go. The loco wiring doesn't match the color coding in the instructions from Digitrax. I've installed DCC in engines with quick plugs, or soldered them to a board, but with this I don't know exactly where all the wires need to be connected to.
I appreciate and thank anyone for their help or advice. You can tell I'm not an expert at this.