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Hi,

Working on my K-Line TMCC  PA-1 AA.  Adding smoke and electro couplers.

Traced and mapped all the connections from the Receiver board and was getting ready to connect when I noticed something odd.

According to the Lionel wiring diagrams, the middle pin  on the smoke unit is chassis ground and the two outer pins are AC Hot. See attached PDF

On the K-line smoke units they seem to be wired the same way but they have a red wire for both of the chassis ground for the fan and resister.

And black for what should be hot. Two units the same way. Am I missing something. Should the Black wire go th the Smoke output on the TMCC board?

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The real key is see which input power lead goes to the rectifier to generate the fan voltage.  That is the hot lead from the R2LC smoke output, the other wire will go to chassis ground (wheels).  Note that it's not always the red wire that is positive on some of these, I have several Lionel smoke units where the black wire to the fan is the positive lead. 

If the black wire goes to one end of the diode, that's the end that goes to the smoke output from the R2LC.  You can test the unit by applying about 12V from a transformer on the two input leads.

 

FWIW, the "thing" on the smoke unit is a 78L05 (or equivalent) voltage regulator, the "thing" that controls lights and couplers on the R2LC/R4LC is the MAC97A6(or 8) triac.

Thanks John,

I try to learn something new everyday. I knew that the "thing" that controlled the smoke was a triac. I bought some per your recommendation from DigiKey to fix a couple of R2LC's  that got toasted by a shorting K-line puffer unit. Now I know that they can also look like voltage regulators. Not like the one that I replaced on my Mogul. That had the 8 ohm resister and it was much bigger.

 

But I think I know how to hook up now. Can the ground go to the ground pin on the motherboard that is right next to the smoke output? I traced it to Pin 3 & 4 on the R2LC.

Thanks for your advice.

Those are AC inputs so they don't really matter, but Lionel and K-line smoke units are chassis grounded through the screws and metal of the smoke unit.  So which ever wire has continuity to the screws and body of the smoke unit, should be black and chassis ground.

 

Normally the first position is AC center rail in, the second is AC ground, and the last is also AC center rail but is normally jumped to the other AC input.  This can be separated if you wanted to drive the fan off a chuff switch.  G

Ok thanks guys.
In this case it is wired as GGG says and as the Lionel schematic says it should be.
For some reason k-line swapped both the red and black on both the AC input and on the DC can. On two smoke units. NOS.
I was wondering if this was for a specific reason. These units were originally used in the Skyline Diners.

So as John said. Chassis ground to the wheels.
The other end with the diode to the smoke output on the motherboard via the R2LS.
Thanks.
Originally Posted by GGG:

Those are AC inputs so they don't really matter, but Lionel and K-line smoke units are chassis grounded through the screws and metal of the smoke unit.  So which ever wire has continuity to the screws and body of the smoke unit, should be black and chassis ground.

 

Normally the first position is AC center rail in, the second is AC ground, and the last is also AC center rail but is normally jumped to the other AC input.  This can be separated if you wanted to drive the fan off a chuff switch.  G

George, the smoke output from the R2LC in command mode is half-wave rectified DC, not AC.  The polarity to the smoke unit DOES matter, connected backwards and the fan regulator will not function.

 

Which half?    Understood, and as I stated it does matter even if the R2LC was full wave.  Since the element and the smoke unit is grounded to the chassis, you have to get them right or you have a direct track short.

 

Additionally, I have seen many with the trace cut and a direct AC center rail input for the smoke regulator and the R2LC only feeds the element.  Pictures attached are an example of a similar but side connector basic lionel smoke unit.

 

Red is AC CR to element, Black is AC outer rail to the element, smoke unit frame and smoke fan, brown is the smoke regulator AC Center Rail.  A small trace can be bridged with solder and the brown wire would not be needed as Red and brown would connect on the PCB.

 

This is why some Lionel engines had a fan still running when power was applied even if commanded off via R2LC.   G

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I want to thank John and GGG for their help. Also the guy in the parts dept at Brasseurs.

I finished the smoke unit install.
I had to remove the rear Molex connector and solder the power wires directly to the board to get the necessary clearance.
But working as expected.

If not for you guys, I would have made two major wiring mistakes.
Now I am waiting for my Mini Commander Ex for the rear unit.

Also completed my FA ABA upgrade with a DC Commander. Runs nice at slow speed and see no need for cruise. Let's me run my 9 car Fleet of Modernism consist on my Command layout instead of running conventional.

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