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I was given this Lionel conventional General type Christmas steam engine.  When I first got it, the light would power up but it would not come out of neutral.  I took it apart and discovered the E Unit Board had some burnt looking components on it and the plastic bracket that held the board was melted in one spot.  I ordered a new board.  I see where all the wires go except for one of the black wires coming off the smoke unit.  When I took it apart, it looked like it was stuck or soldered to the back of the E Unit Board, between the board and the mounting plate holding the board, on the same terminal where the black wire on the front of the board was attached.  This seemed odd to me and I was wondering if this is where this wire is actually supposed to go.  Would there be a schematic of this anywhere? Here are a few pictures.  Any help is appreciated!





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The black wire from the smoke unit does not need to be attached to the reverse unit. Regarding the smoke unit: one wire should be grounded to the frame, usually the screw that holds the cross head guide to the shell. The black wire can be attached to the center rail pickup. There is usually a wire that goes from the pickup to the reverse unit. Further, usually 3 wires are wire nutted together 1) the center rail pickup, 2) a wire from the reverse unit, 3) the wire from the smoke unit. There is nothing on the reverse unit that controls the smoke unit. Some loks had a smoke unit on/off switch. Lionel did away with it as a cost saving measure.


Thank you Ride the Rails, Jon G and ADCX Rob!  That's exactly what I was looking for.

For clarification, should I connect that black wire to the others in the wire nut like the above schematic shows or to the board as Rob mentioned?  I am running conventional around a loop so it won't be sitting in neutral very long.  I don't want to fry the board again.  Thanks.


Thanks Rob, I will follow the diagram.  The way it was wired probably caused it to fail in the first place.  Yes, the General's are a pain.  I had to study it for a while to figure out how it even came apart.  There is not a lot of room in there.


Well, based on a couple of responses, you have a couple of options. As ADCX Bob mentioned, attaching to the PCB would suspend its operation while in neutral.  I don't know where it would need to be attached for that.  It appears that was not thoroughly thought out by Lionel as it damaged the PCB.  I'd go with the wiring diagram as presented by JonG.  Keeping in mind that anytime there is power to the track, the smoke unit heater will be active. The heating element, as you can imagine, has a high power draw.  I wish Lionel would have kept the on/off switch. In any event,  keep fluid in the smoke unit.  Don't drown with smoke fluid as to much will prevent it from operating properly (see note below).  I use Seuthe smoke fluid and put 3 to 5 drops in (sorry, it's not an exact science).  Something I also do is put a few drops in if I'm not going to run it for a while.  It keeps the wick material moist, the intent is to keep it from drying out.


note: the chamber that contains the wick and various other pieces of the smoke unit was/is supposed to be a sealed (based on my observations) unit.  Some were not assembled correctly, i.e. not sealed properly. Therefore, over filling the smoke unit could cause the smoke fluid to seep out around the area where the smoke unit was supposed to be sealed.  Then you get smoke fluid on the under parts of the lok and possible on the track and in extreme cases on the material that the track is laying on.

Last edited by RideTheRails

Well I finally got the new parts in and got around to wiring the new board in.  After everything was wired up I put the engine on track to test it.  The engine moves and switches direction in forward and reverse, but it goes real slow and seems a little choppy with about 75% throttle on a z1000.  The two components on the board circled in red get very hot to the touch and I thought I saw a little wisp of smoke coming from the board.  Could the motor be going bad?  Any help is appreciated!  Thanks.



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The smoke unit is not directly connected to the board.  The positive from the smoke unit goes to an on off switch and then is connected to the motor positive along with the red wire from the board.  The negative from the smoke unit goes to frame ground.  Before, they had the ground from the smoke unit running through the board.  Here is a video of the motor running with a 9v battery.  It looks to be spinning the same RPM with the battery as when connected to the engine.



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Looks like the transistors blew on the old board if they are getting that hot on the new board best to find out why the motor is pulling so many amps. Might check the the rest of the drive line to make sure nothing is binding.

if the transistors do blow you can replace them. I think they are TIP31 and 32. They are rated at 3A. I typically use 6A transistors when I replace them, the E units at our club get used a lot and tend to eventually breakdown.

@ADCX Rob posted:

It should be much zippier than that.

To preserve the life of the reverse board, the smoke unit should not be connected to it in any way, even through the switch. The elements go bad - to a short - too often and take out the power transistors.

I disconnected the smoke unit positive from the switch to see if that made any difference with the motor and the heat in the transistors.  It didn't.  With the motor running for about 30 seconds at 50% throttle the transistors got hot enough to only leave my finger on them for a sec or 2. 

Is it safe to assume the motor is bad and pulling way too many amps, thus heating up the transistors?

As far as rerouting the smoke unit power, can I tie that into the wire nut that has the 2 wires from the pickup rollers as well as the gray wire from the board?  I don't see any way to power the smoke unit without it being tied into some wire that connects to the board.


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