Lambertville, MI
Does the actual sound in game raise or lower on it's own without you touching the volume? I had a Stern SM that had a nasty hum, but the sound was messed up along with it in the way described above. After much messing around with tightening down screws etc...I found it to be that someone installed the wrong type of diode on one of the main boards. After replacing the part with the correct one the hum went away and the sound returned to normal. My point is make sure that no one modified the boards with the wrong component. Sometimes hard to find, but can cause this type of problem.
(Topic ID: 168323)
