So I got a Vivitar 285 from my grandpa, looks to be in perfect condition, and it hasn't been used in many years. (Over 10 probably) There's just one problem. It won't turn on and fire! I put fresh batteries in it and it still doesn't work. It could be me not knowing how to work the thing; I just flipped the switch on the back so that it shows red and didn't hear any noise of charging or see the red light come on. What's the deal? I would really like to use this flash as opposed to my other one that I don't even know the brand of. Could it be corrosion? Am I just making a common mistake? Any help is greatly appreciated, I don't want to have to throw this piece of equipment away.