Thanks very much for your reply. It is helpful to see what's inside the box at the end of the tracks.
I've read a lot of threads on tambour and they cover a lot of ground. But, I haven't read any about how to remove
this type (vertical slats, horizontal slide) of tambour door. I've studied my particular problem a bit more, lying on my back and using a flashlight. It seems the best approach will be to remove the credenza top. It appears to be held in place mainly by screws to aluminum L-brackets, or screws directly into the wall. There may be a couple of rivets in there as well. I think if I remove all the fasteners, and the credenza top, I should gain access to the tambour roll.
As for the horizontal slats/vertical roll in the microwave/hutch cabinet. That one does not have spirals like all the rest of my vertical slide cabinets. It just has an L-shaped track on each side and the tambour slides out of the way into the cabinet top. There is a piece of plywood up there that partly covers it. At the back of the tracks on top there are two screws that look like they are there to prevent the tambour from sliding out the back. I plan to remove these two screws and see if I can just slide the door out the back. That one should be easy—if it works.
I'm just in the "mulling it over, making plans stage" right now. I am in the middle of replacing all the blue plastic rub rail inserts on the outside (and around the AC on the roof!). Pretty much just and R & R job. But man, it's amazing how much dirt and grime can get into things in 40 years!
If anyone else has any comments/advice on my tambour project, it will be much appreciated. I haven't torn anything up beyond repair—yet.