Gonna add a composite input to it, if I can. Some research I did last night gave me a pretty good idea as to how to approach doing so.
Morbidly curious what the 'charge' setting on the power source switch does. Was this thing sold with rechargeable nickel-based C cells instead of disposable alkalines? The battery cover has another 'risk of electric shock, do not open' warning on it that specifically says "do not remove cover (or back)" implying that they don't even want you to open the battery cover, so that points toward yes. But inside the battery compartment, there's a sticker that says '9pcs C Size Alkaline Batteries,' which implies that they were ordinary disposable cells, and that's what it had in there when I found it. Will have to poke around with a meter sometime and see what there is to see.
