My projector advances all by itself sometimes, or advances too
many slides during a tape synchronized presentation.
You may be using a model which has an automatic timer and have
turned it on inadvertently. On newer Kodak projectors the timer
is a sliding switch near the power switch. On older Kodak projectors,
the timer is a plastic sliding lever on the rear of the machine
below the Kodak nameplate.
If you have an older model projector, it is quite possible a part
called the timing disc may have torn. This will cause the projector
to advance at regular intervals even with the timer turned off.
Having this repaired can be quite expensive if the part is even
still available. However, it is very simple for an authorized
service center, like United Visual, to disable the timer and restore
normal operation. (Except for the timer, of course.)