Adding a sound decoder to a Bachmann Gas-Electric Doodlebug -- Part 1

The Great Northern "doodle-bug" 2320 is a regular runner on the 4th Subdivision, but it sadly has no sound. Adding a sound decoder to it has been on my to-do list for a while, as seen in this previous post.

At the Railfest show in Kirtland, Ohio this past weekend I picked up a Tsunami 2 TSU-1100 P. N. 885004 "For Baldwin and Other" decoder. This decoder includes files for a "Galloping Goose," Dual Whitcom, and GE Cummins prime mover sounds, any of which would be more or less appropriate. I also purchased an 810140 Current Keeper and an 810078 speaker to complete the install. In talking with other members of Division 12 (Brad White, Mike Hauk, and Doug Sandmeyer) while we manned our table at the show, their consensus was to tear out the Bachmann board, as it does not have a great reputation, and start from scratch. The one caveat they all suggested was to use the existing eight pin and light board to identify the wire sources and mark them with paint or tape, rather than cutting wires willy-nilly. Today, I canvased my parts bins and found some LEDs and resisters that may be an appropriate choice as well as some shrink tube. It looks like I now have the materials on hand to tackle the project. So, the decoder install adventure begins.

It has been years since I installed a decoder, and I have never hardwired one. So, for me, the first step was to do some research. Among the many Soundtraxx videos on YouTube was this one on installing a similar decoder in a K-27 that gave me an overview of the process.

The first step in the video was to remove the tender shell, so my first step was to remove the shell or body of the doodlebug. Using a chisel bladed hobby knife, I slipped the blade between the shell and the frame along the underside. I slipped toothpicks into the open gap to hold it open while popping the other tabs to remove the shell.  In the photo, the toothpicks roughly point to the four tabs I found located on each side. Working slowly and carefully, I was able to remove the shell without any damage. Upon inspection I found several issues. One, that I knew about going in, is that the figures in the coach compartment are too "tall" and need to be reconfigured. It appears that although it should be relatively easy to identify wires, one wire to the back truck had broken at some point previously and I will need to re-solder it. Finally, it looks like the speaker I bought at the train show is going to be too large for the space behind the motor where I planned to locate it. I may need to add a different speaker to my new shopping list along with a pencil-tipped soldering iron and solder more appropriate for electronics.

That was it for the first day of this adventure. The next step is to identify and tag/flag all the wires as I prep to remove the Bachmann board and plan placement of new components.