I just now noticed your post.
I have taken a break from it, but yesterday I returned to it.
I am now concentrating once again on my original assumption the problem is in the output amp.
I found several open transistors, including the finals. I replaced them. I found more, and am taking another break from it. The lower board is not anywhere near as easy to work on as the top board. I will be back at it again. I am determined to not let this unit win the fight.