you should be able to see if they come on by plugging them in. They do make those cheap video games that look like a joystick (they are cheap at WalMart) and THOSE plug into the front AV ports (like in the pic unknownk posted)....I would pick up one of those maybe just in case where yo can show it is working in your pic....will cost you $10, but since you have 20-30 of these things...the upside is worth it...that is what I would do.
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