Originally posted by jatrax Possibly some dirt or grit in the button. Try this: turn off the camera, hold it upside down, so the button is down. Then push the button firmly all the way in, repeat maybe 20 times. Sometimes this dislodges a bit of stuff that got stuck there.
If that doesn't work, maybe try some contact cleaner? Make sure it's the no-residue stuff as some of them contain oil. I've fixed a few jammed things with it, as well as the e-dial on my kx that was non-responsive after getting splashed with Redbull at a festi last summer.