raise your playfield & un-plug your recently replaced optos (4pin plug orange/black/grey wires), start a game and wait to see what happens, if nothing happens or if diverter flips once or twice and then stops completely you do indeed have an opto problem - plug it back in and start another game just to make sure problem returns.

if diverter continues to actuate with the optos un-plugged you probably are having a driver board related issue and needs much more investigation

like some one above mentioned, test the opto voltages on the rear of the optos, should be 12-13volts on each, if one is low (1-3 volts) you may have the new opto soldered in backwards - they only work in one direction, this doesn't sound like your problem since yours works in test mode

the receiver (black) opto at this location is very sensitive to having the emiter lined up correctly and sometimes takes a bit of bending / tweaking of the mounting locations on the ramp to get perfectly aligned, if not aligned correctly you will indeed get multiple signals from your optos

finally make sure opto mounting screws are snug once you sort out your problem

hope this helps ....

pull your multi-meter out and measure voltage on the solder pads where the two wires are attached on rear of each opto pcb, since the pair of optos in question are located on the upper end of a ramp, you can simply un-screw each opto and measure while holding in your hand of course this measurement is done while machine is turned on-)

hope this also helps