The issue I have with Sensortrons for the most part is spotty acceptance. Even if they are adjusted all the way to accept anything, they will still reject at least half the quarters. I had one the other day that worked ok to start but once running the timer if any more quarters were added, it would reset the timer. Timer is a dixmor LED 7 and yes, I tried swapping timers, disconnecting horn, etc. Replacing the acceptor fixed it. I have one right now that always rejects the first quarter and then will accept quarters after the first reject. I will admit that I haven't tried cleaning them yet and they are probably pretty old. I have been replacing with Slugbusters as I have had pretty good luck with them at my other wash and they are cheaper. If they can be repaired for $40, I may stick with them because I don't mind paying a little more for a repairable acceptor.