Both Weaver and 3rd Rail use TMCC for their command control. Depending on what triggers the chuff, something may have slipped in your engine. If there is a trigger switch inside the engine itself that is actuated by a cam or by the side rods, check to see if these switches are working. I have several engines from Weaver that the sound is actuated by a small magnet cemented to the inside of a tender truck wheel. The magnet moves past a reed switch mounted to the truck frame, and this causes the chuff sound to fire. Check to see that the little magnet is still in place and that the reed switch hasn't moved too far from the magnet.
If the sound is actuated by the motor speed governor or speed reader, check the space between the reader and the white/black tape on the flywheel itself. Then of course, there could be problems in the sound board or speaker.
Try these first.
Paul Fischer
