I don't have my gun handy to look at, it's on the way to Briley for new firing pins, but I've had the butt stock off a number of times and even converted the ejectors to extractors for a while so I think I may be able to steer you toward where to look for the source of the problem.
When you drop the tumbler (hammer) on a barrel, a rod, which projects out of the lower edge of the receiver near the hinge pin, kicks out and flips the ejector scear in the forearm. Each ejector scear pivots on a pin through the side of the forearm. (As a side note, if you drive these pins out and remove the sears, the ejectors become extractors). I don't see how the rod that's attached to the tumbler can kick out if the tumbler doesn't drop (unless it's broken) so I'd look for something that might be pressing on the ejector scear (like stray crud). If my memory serves me correctly, the right tumbler fires the bottom barrel and so the bottom ejector scear trigger rod would be on the right.
If the top of the ejector scear tips away from the receiver, the ejector doesn't "pop" it just gently extracts. If the sear tips back toward the receiver (because it's stuck or the ejector trigger rod is projection from the receiver), the ejector catches on the scear, which compressed the ejector spring, until the curved part of the ejector slips over the top of the scear and "pops".
Again, if memory serves me, there is a tiny spring behind the ejector scear which is supposed to return it to the extractor position when the action is fully open. I would expect that either the spring is broken or completely gunked up with something. I'd spray some action cleaner in around the ejector scears and work them by hand to try and free them before I'd start driving pins out because springs this small tend to make the jump to hyperspace if you are not really careful.
I hope I haven't made the matter more confusing. Maybe this will help you at least diagnose the problem before you send it for service.
Thank you very much for the info. I can sort of visualize how the extractors/ejectors work now.
It would seem from your explanation that if the small rod that projects out of the receiver to signal a barrel being fired is not stuck in an extended position the problem would almost have to be in the ejector sear.