I just bought a vivitar 285 hv used from a local camera shop. It worked perfectly in the store, but when I took it home all of a sudden it wouldn't pop. The test button would work maybe once out of 20, and the same thing with the hotshoe. I drove right back to the store, and they couldn't figure out what was going on either.

They gave me another 285hv with a broken foot and in rougher shape but worked perfectly, and I kept the broken flash. My reasoning behind this versus getting a refund was I could certainly make one working flash (maybe two) from them. I've ordered a metal shoe from eBay to replace the plastic ones with once it comes in.

At first I thought the foot on the original 285hv was bad, so I desoldered it and tried just tapping the leads together. That works but not consistently. Any ideas?