OK. Now it's time to prep the frame. In order to accommodate the speaker and the decoder, you'll have to mill the frame a bit. The following photo shows the areas in black that need to be milled off each side of the frame: Be VERY careful when cutting/milling around the motor mount hole at the top of the frame and around the cutout for the flywheel - too much cutting here and you'll cut through the frame (ask me how I know this). After you are done, you'll want to insulate the area of the frame where the motor contact strips come up to contact the circuit board. I use kapton tape for this. We won't be using the circuit board, obviously, so you want to make sure these strips can't accidentally contact the frame and cause a short: Here's a series of three photos, showing the cut frame; where the speaker will go on the rear of the frame, and the frame reassembled with the motor inside and the kapton tape insulating the areas where the motor contact strips are. The last prep step is to cut a small piece of the old circuit board to use as a place to solder the decoder power pickup wires to. My RS-11 had an old Atlas decoder board in it that I scrapped, but you can do the same thing with the standard light board: That's it for all the prep steps. In the next part of the tutorial, we'll install the decoder, headlight LED, and speaker. John C.
John, Great write up and photos are a big help. Two questions; what Dremel bit do you use to mill frame? Also, how shallow can the speaker enclosure be and still be effective? Thanks in advance!
i use use a diamond cutting wheel for the frame mods. A carbide cutter would work, too, but I like the thinner cut of the diamond wheel. i think you could probably get away with 5.5 mm of height for the speaker, using 5mm-wide side strips plus bottom. john C.
