It could be a problem with the actual timer. Did you try to swap a rejector with one that you know is working properly? If you are jiggling the
coin in the slide tray to get it to accept, it must be the rejector. The only way to be sure is to swap it to a vac that is working, and try to see if you get the same results (having to jiggle the
coin tray to accept). If so, the rejector has a bad connection or kicker foot, if not a bad wire to the timer or the timer itself. Try the same thing with the timer. Switch out one from a vac that is working properly etc. Send the rejector back for repairs, buy a new one, or upgrade to something else MA800, Slugbuster II, Microcoin, Etc.