Jim Yanik wrote:

I'm still trying to figure out why epoxy was used to hold a SMD on the
board? thermal-conductive epoxy?


I've never seen epoxy used to hold a part to a PC board. A tiny dot
of a red glue was used on our boards, and it would release when you
desoldered the transistor leads. Any rework at the factory level used
very thin solder wick to remove the solder, and a very thin curved
'dental pick' to lift each lead while the joint was still hot. If the
glue was still holding, you touched the transistor with the soldering
iron to free it. If you worked fast enough, the glue was loose when you
unsoldered the last lead.

If I can find my old rework tools, I'll make a video & put it on
Youtube. I'm finally able to spend a little time in my shop, after 5+
years of health problems.