From the test you did below it sounds like its a problem with the opto which is a good thing. Before you change it again can you confirm what you changed. Can you also confirm how yours is wired compared to the below pictures. We don't want to make it worse than it is.
I replaced a complete set, pcb, housing, led as a unit, no assembly on my behalf.
I know the Optos were put in the same way, but as a side note, my tz has three sets wired like my rfm and one set as yours, so I'm confused.
So you think its the Optos even though I replaced with a new set. I will try another and see what happens if you think I should try another set.
