The FX-3 cameras are very well built and designed and easy to work on. If you open it up you will see. I have not encountered the problem you mention. On thought is that the screw for the 'snap' lever is loose. There are two screws holding the plastic lever in place you can see from below. With the plastic lever off you can see the screw. In is REVERSE THREADED so you turn it the opposite way to tighten it.

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