Can you post some closeups? Perhaps make out the manufacturer name on the board?
Put two batteries in and use a meter to measure the voltage from the battery pack.Problem is I don’t know if it would be a nine or eighteen volt
I have a Fine Art C&O 2-6-6-6 Allegheny. I got it second hand. It has sound in the tender. There is a separate controller for the sound. The controller takes a 9 volt battery. There is a provision in the tender for a battery holder as well but it didn’t come with one. The battery holder holds two nine volt batteries. Problem is I don’t know if it would be a nine or eighteen volt for the sound system in the tender. Any input is appreciated