Quirky MTH smoke unit in a stacker upgrade.

I usually find 99% of the time it’s a self inflicted GSW that trips me up, …..,before getting all super technical, ring the wiring for the smoke heater all the way back to the tender harness where it plugs into the board,……of course, do this on the bench, not powered up,….

Pat

Forgive me Pat, I'm a little electrically illiterate, when you mean ring, do mean patch the wiring or trace?
In context, would that mean running the brown wire on the smoke unit in the engine to the brown wire in the tender, before the tether?

Use a good digital volt meter with a continuity tester. Even half decent cheap meters have a beeping sound that proves continuity. This will allow you to test the circuit from the smoke unit, into the engine harness, through the tether, & into the tender harness.  Don’t assume you have a board issue until you’ve verified the wiring is good. Could be a break anywhere in that chain. Pinched or broken wire, folded pin, cold solder joint, bad tether, …..the list goes on & on,…..

Pat

Doing some testing with the tester revealed the source of the issue. 
This engine has an older boiler MUX setup than the newer ones with the wireless drawbars. Rather than being on the MUX board, the smoke unit is directly wired into the main tether bundle, EXCEPT for the lilac wire (which I think is the ground...?) The liliac wire runs to a spot on the boiler harness receiver that has a pin, but no corresponding receiver on the MUX harness. The MUX harness in question is from an engine that had a wireless drawbar, so it has plugs for the smoke unit motor and heating element on it.  Oddly enough, all the lighting is still all controllable from the current MUX board using the current harness (except for turning off the class lights, but that seems to be how this particular sound file is programmed.)

I'm curious where to go from here. Can I wire the lilac wire on the boiler pins directly to the pink thick wire, or will I have to do something else?

This is where your curve ball is, …..it’s never a good idea to mix match harnesses from PS2 & PS3. Some of us were just discussing this the other day. MTH had no problems altering harnesses to fit a specific locomotive. You’re actually very lucky things haven’t gone poof……..you’re gonna have to find the path from the board in the tender to the smoke resistor in the engine,…..don’t assume something is ground, …..

Pat

Lovely...
I'm going to assume you mean the lilac wire in the engine to the lilac wire in tender?

Oddly enough, both of these engines were PS2 3 Volt at one point. By the end of this I'll probably just have a non-smoking Frankengoose.

Update:
Tracing the lilac and pink wires has revealed that they follow the path found in the diagrams in this post.

The lilac wire coming out of the smoke unit appears to likely have aligned with a slightly different MUX harness. Given how this engine was put together, MTH probably used a different MUX arrangement, as the smoke unit connects to the drive block, rather than the shell like most engines of a similar ilk.

@BBasalik posted:

Update:
Tracing the lilac and pink wires has revealed that they follow the path found in the diagrams in this post.

The lilac wire coming out of the smoke unit appears to likely have aligned with a slightly different MUX harness. Given how this engine was put together, MTH probably used a different MUX arrangement, as the smoke unit connects to the drive block, rather than the shell like most engines of a similar ilk.

Well, if you have a portion of the harnesses that’s PS3, there’s no mux board in a PS3 arrangement. There’s a boiler board, but it’s a bit different from a Mux …….your best bet is going to find out which two pin outs control the smoke resistor and duplicate that exact same path,……don’t touch anything else at this point if everything else is  working as advertised….

Pat

BE VERY CAREFUL tinkering with the wiring.  The PS/3 boards are not at all forgiving to mis-wiring!  Connect the wrong things together and you'll be shopping for another Stacker Board.

John, I'm close to just converting this to a straight PS3 upgrade kit. No more MUX.

A little bit of history on this;
The Blue Goose (20-3194-1) is from 2005 and is a PS2 3 Volt Locomotive. I pulled the blue battery out of it when I got it, but it was missing the main board in the tender, and MUX boards in both the engine and tender. The boiler was also missing the MUX board and harness.
The donor locomotive is a Premier Royal Hudson (20-3313-1,) also a PS2 3 Volt from 2008. It's tender and main board were destroyed when Catzilla decided that it and him could not occupy the shelf together. (The shelves now have an acrylic front panel. Catzilla is very unhappy it can no longer lord over it's domain.)

Looking at the boiler tether and port again, everything is as it should be except for smoke related wires. The key difference between the two is that the tach reader colors are tweaked slightly. The tach reader works non the less.
What is missing is that in the harness, the green and brown wires terminate to nothing. The receiver has blank solder pads there. Like-wise the receiver has lilac wire coming from the smoke unit that terminates in the exact center. The harness has no wires there.

I still have the other boiler harness from the royal hudson. I'm tempted to use it as a substitute for all the wires in the boiler, as then the everything would align. The only caveat is that I would have to redo the engine wires and main harness.

The other option I could do is just have the engine have no smoke. Everything else works.

To be honest, you’re flirting with disaster,……there is no way we can tell you what wire goes where beings it’s pretty much mismatched harnesses…..you can go for broke, but it might cost you the board set, …..this stuff is just not forgiving…….sorry to disappoint…..

Pat

I think for now I'll just leave it as it lays. With the exception of the smoke unit, everything else is working just fine. 
Besides, probably running it without smoke will keep the blue crisp. Some of my other brightly color units with smoke are starting to look a little worn.

If you're missing your mux board in the engine and tender you are missing light and smoke heat in the engine because you are missing PV made on the engine mux.  So what did you actually do harness wise with this upgrade?   Not sure how your lights are working but you imply they are.  G