You are correct that you don't need a battery, although it's useful to have one for conventional operation. Its function is to keep the sound going during power interruptions (direction changes, etc.)
It's highly likely that your problem is in the EOB. Have you tried turning off the cruise? If the cruise is on and you turn it off, that might just help.
There are also some tweaks and adjustments to EOB that are detailed in the instruction manual. I don't think you can do anything with them without TMCC, but I'm not sure because I don't run conventional myself. My best guess is that the problem is the speed sensor, but it could be all kinds of other things as well. If you don't want to remove the shell and you don't have anybody locally to do it for you, the best advice I can give you is to send it to Weaver, even with the border hassles. I'd also advise getting a TMCC setup or the "lite" version of Legacy, which uses the same control configuration as TMCC and will operate your unit just like TMCC. I'd advise getting the complete set including the handset, rather than relying on the DCS connection. When you are trying to test something, it's always better to eliminate as many intermediate steps as possible. You can still run the locomotive through the DCS remote and a TMCC base station, but it's best to have the TMCC remote on hand for testing when needed.
