Correct, just the standard 5V small fan motor. That's the good thing, MTH started with a solid design and continued using it from what I can tell for 20+ years using the same parts all that time.

They even have it under the quick access list of parts https://www.mthpartsandsales.c...ts/240?type=products

Or, if you are unsure if the board is bad or just need a whole new unit

Also sometimes the plastic impeller can crack and be loose on the motor shaft (I searched for "impeller")

Thanks, Vernon, but it seems like something has been changed.  I ordered some of these, but burned out a couple right away after soldering them into the old board.  I also tried using one off a newer smoke unit, and again, the motor heated up and quit working.  I know the smoke unit itself is working. 

If the fan motor is being killed by your board, the 5V regulator has died, and the board won't work anyway.  I'd consider replacing the regulator if it's burning up smoke motors.

... click on graphic to expand...

That makes sense, but would the actual smoke unit still be working in that case (it is-).

Everything but the fan would still be working.

OK, thanks!

I edited and tried to make more clear the separation in the drawing.