I rebuilt an HO scale Walthers Mainline RSC-2, because the motherboard and decoder are visible in the cab windows!

BEFORE: Such a basic model locomotive doesn’t need such a huge motherboard.

AFTER: Due to the long hood’s slightly lower height, I milled the frame for some additional room and relocated the speaker, Decoder Buddy, and ESU LokSound V5.0 58429 decoder.

Success!

LEDs have also been replaced, and No. 1109 is now in service.

More on The Carolina Sandhills Lines thread in the Layout Engineering form.
DFF