For those of you interested in hard-wiring a decoder (e.g., a Tsunami sound decoder) inside the tender of the Hiawatha and removing the big space-consuming circuit board, here's the wiring arrangement. You'll notice that the plug from the engine has 4 wires, then a space, then two more wires. It hooks to a 7 pin socket in the tender. Counting from the end of the plug that has the four wires, here's the wiring arrangement for DCC: Pin 1 - Red (Track +) Pin 2 - Orange (Motor +) Pin 3 - White (headlight) Pin 4 - Blue (function common) Pin 5 - blank Pin 6 - Gray (Motor -) Pin 7 - Black (Track -) What i did in installing my Tsunami was take a cut-off wheel in a dremel and cut the circuit board just behind the large diode at the front of the board, leaving enough of the board to stay screwed on by the two screws in front. I de-soldered the large diode; these pads can now be used for track power and if you turn the board over, you will see that there are board traces for the orange, gray and blue wires that you can scrape clean and use for soldering pads. I wired the white wire directly to pin 3 on the plug since I didn't see an available trace after I cut the board (there's got to be one there; I just couldn't clearly follow one to Pin 3). The TSU will now fit very nicely in front of the speaker cutout with just the front tip sitting on what's left of the circuit board. Add a speaker and off you go. John C.
