Which is the most logical culpret? The timer or coin exceptor? Neither components can be set for 4 pulses per coin. It doesn't happen all the time, so it's one of those intermittent issues. The ones that are fun to solve! When it does it, the horn will even pulse 4 times. I discovered this late last night, thanks to an honest Gramma! Makes me wonder how long I've been giving out free time!