The smoke regulators are problematic, and of course you already found out that Lionel declared almost all of the TMCC and early Legacy parts obsolete and deep-sixed them.

My solution to smoke regulator failures with TMCC is to lose the smoke regulator totally.

• Replace the existing smoke resistor with a 20 ohm smoke resistor
• Wire the smoke output from the motherboard through the smoke switch and on to the smoke unit power.

This will still allow command control of the smoke, you just lose the smoke level settings.

Thanks John.

I used you suggested Digikey item from 2017 post for the 5W

Where to find SMOKE RESISTOR / CERAMIC / 20 OHM 3W 5%

.I ordered 10 for the discount since I also have a total of 6 smoke TMCC engines. they may go too!

Yep, just crunch the outside ceramic shell and out pops the perfect smoke resistor.

I have the 20 ohm cracked resistor to replace my 8 ohm. The fan runs from a battery. Not sure how to find the right connections for the smoke board. I am trying to figure out if there is a way to cut and splice existing wires to the smoke board and from the dead ACRG rather than cutting the wire ties to find the smoke AC connections on a mother board. It looks like a big rat’s nest to me.

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INFO from posts that are related:

(JOHN’s) My solution to smoke regulator failures with TMCC is to lose the smoke regulator totally.

• Replace the existing smoke resistor with a 20 ohm smoke resistor
• Wire the smoke output from the motherboard through the smoke switch and on to the smoke unit power.

This will still allow command control of the smoke, you just lose the smoke level settings.

“When you do the repair, the easiest way to do it is to cut the new regulator wires to about 2" and just splice into the existing four wires.  When you cut the old regulator out, leave yourself plenty of length for the splice.  Trying to follow the wires to the final connections is doing it the hard way.”

“you have to isolate the traces of the smoke element resistor, and wire one side to ground, the other side back straight to the feature out on the radio board. First, you need to verify if your fan still spins like it supposed to, and your radio board doesn’t have a cooked smoke ( feature ) output. If those two items work, you can proceed with a bypass. If not, another solution would be GRJ’s super chuffer and chuff generator. You can rebuild that smoke unit, again, isolating a few items to work with John’s stuff….so there are a couple options for repair….”

(JOHN’s instructions)  Well, you do have to wire the smoke heater to pins 5-6 of the R2LC, that output is no in the picture or your description.  Also, note that the 5W resistor has to be "cracked" to expose the internal wirewound resistor, you won't fit that big square block into the smoke unit.

This is the exact resistor I "crack" for 20 ohm smoke resistors: Yageo SQP500JB-20R, and if you want 27 ohm smoke resistors, use this one: Yageo SQP500JB-27R

I just put them diagonally in the vise and squeeze enough to crack the ceramic, it drops away and you have your smoke resistor.  At the rate I go through them, it saves quite a bit of money.