This may be more of an observation than a question. I snapped my trusty old (1980?) Vivitar SMS 30 onto my new D3200's hot shoe last night and couldn't get it to fire in any mode even though test button worked fine. I fought it for a long time. Eventually I dug out another flash someone gave me, a similar Vivitar 3500, also from the early 1980s, and it worked like a champ. (Long flash charge time with NiMH but fast with alkaline.) Both are simple flashes with two contacts and manual mode so all the camera has to do is complete the circuit. I've used both with optical slave triggers. They seem to fit OK. So, what would be the difference? Has anyone seen behavior like this, or am I the only one trying to bring photo dinosaurs back to life? (P.S. SMS 30 trigger voltage reportedly around 7V.)