Left flipper doesn't work or strikes a couple times sometimes when depressed. Started as an issue after it warmed up, now it's happening cold. I'm new to ownership and could use some advice as to what to check. I've looked over the leaf switch on the button, looks good. All the solders appear solid and well done. I don't think it's connections, could it be a bad coil or flipper board? Any advice would be help. Thanks!