I've owned a F2A for 25+yrs and it has been trouble free for all that time. Except recently it has started to produce a fault. Only when it is used on a tripod with a cable release (nikon). Then I get I thin line ( about .25mm) of overexposure on the far left edge of the frame. This is when viewed from the emulsion side. I've tried the cable release on a FM and that is fine. It is annoying becuase I like to print fullframe with a thin keyline masked down from the rebate. Any thoughts?