I own and use a 45S but have never experienced this problem. I originally referred you to the "dead thread" (see: "reason for edit") because it had the only answer that I know of. The symptom you describe is not normal, but it has been heard of. The solution usually requires replacing a part, as was stated in that thread. Sorry I don't have any more details, but since you had revived that thread, I assumed you had read that answer.
I know the answer. But I need a solution on the repair, location of the opti isolator possibly pics of where it is on the pc board. And what exactly we are swapping and where to get a proper replacement.