I've had my Lionel "Moms" diner for about as long as Redfire's had his. The smoke unit on mine just plain died, so I yanked it and replaced it with a Seuthe smoke unit wired directly to the 14 volt accessory lines.
Works just fine, but I wouldn't suggest anything so drastic in your case unless the unit's totally failed.
By the way, the lamp circuitry died on mine as well, so I relit it with lamps and sockets from Radio Shack.
I've had mine since it was brand new in 1995, and it works the same as yours. I've never really liked it.
Jim
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