Hi to all I am converting an Arnold U28C to ESU LokSound. I found two YouTube videos that show "how to". https://www.therailwire.net/forum/index.php?topic=54029.msg740951#msg740951 I designed a speaker box with extra volume that fits into the area above the truck pivot. Remove the contact metal towers and re-solder wires to the truck power pickups. You remove metal from the frame (see the videos), and the case fits between the Arnold PCB and the metal frame. The speaker is "upside-down" for good sound projection. The .stl file is in TinkerCad: https://www.tinkercad.com/things/c5z8zLsQuSU-u25c-n-scale-speaker-case-for-8x15-speaker It is open for use, non-commercial.
Here are the pictures. Yes, I lost the front railing somewhere on my work table... I put the couplers back on after I took the pictures.
