I fixed a couple of atlantic legacy Engines The santa Fe - non - whistle smoke 1484. I think a B&O with whistle smoke. Your unit has two soike units a main and whistle smoke unit. There are a few issue that can cause smoke issues in this engine. The main unit - The smoke unit is not one piece - there was a issue witha rubber gasket that would swell and restrict the fan. Supposedly, Lionel had a different replacement part. Outside of this issue. Some of the issues that can cause no smoke output.
1) "Watch the brakes at the rear of the drive wheels - they are part of the botttom plate. _ i broke a ton of these taking the shell off."
2) Smoke Resistor - It will be a 6 ohm - But, I believe lionel stated to change all the 6 ohms to 8 ohms?
3) ACREG Board that control ther smoke resistor.
4) Smoke Motor
5) Smoke PCB
I would check that the unit is not turned off in command. Check, for fan operation. If someone can chime in. I believe these units only smoke when moving. So, Do you have chuff Sound?
This unit is packed with wiring internally. Its tricky . But, fixable.