The smoke unit you have I believe is the same as postwar 746 sealed units, with the addition of the smoke tubes for steam chest smoke. Even though it is a factory sealed unit it is easy to carefully cut/scrape away the sealant, in order to replace the element. First disconnect and check resistance to verify. Even if element is good you can improve smoke output by adding a small amount of batting beside the element. I think the factory element is about 47 ohms. It is not 27 ohms like most puffer units used. I replaced it with a 35 ohm 3 watt wirewound resistor, from Mouser. Before sealing unit, you can test by just wrapping a small wire around outside of unit, so you can make sure you have correct placement of batting. I just used plain contact cement to reseal unit. A small application on each part, let sit 15 min then press together and use the wire to wrap around unit until dry. The resistor will need to have ceramic coating removed as described in other threads by Gunrunnerjohn. Use high temp silicon to seal where resistor exits unit.
Good luck,
Chris
