Smoking board older Lionel J3 Hudson

It appears the large triac is what is burning up. This drives the smoke resistor. One side of this resistor is soldered to chassis ground. The other side is connected through the smoke on/off switch to this triac. A likely place for a short is where this second resistor lead exits the smoke unit. Check the path this wire takes for shorts. Also check that the resistor is not shorting inside the smoke chamber.

Pete

Check to be sure the side of the triac is not touching the side of the boiler, that will short it out.

You have a short in the smoke wiring I suspect.  That's the reason they usually croak like that.  Check the wiring from the motherboard through the smoke switch and on to the smoke unit.

The triac can be replaced if it hasn't cooked the circuit board bad badly.

Thanks for all the help. I don't know what a triac is. But there is a brown wire from the mother board going to the smoke switch. Color changes to blue going back to the smoke unit. But I think I found the elusive problem. When I wiggled the input blue wire, I measured a drop in resistance (between blue and ground) from 27 to 10 ohms! The culprit is the white insulating sleeve that has burned thru - see photo. Ordered a new radio board today thanks to great Lionel parts supply.  But direct replacement  smoke units are not available. So I ordered a new smoke unit from a Camelback of similar vintage. The bracket is a slightly different in height. So some engineering will be needed. I have a new 27 ohm resistor by itself, but no way to replace the white (fiberglass?) insulating sleeve myself. It needs to be heat resistant.  Afraid that shrink tubing won't work.

Shrink tubing would work. The resistor gets warm but nowhere near hot enough to damage the shrink tubing. It just a bit easier to cut so you have to be careful when you thread it through the hole in the smoke unit top.

Pete

@Bob Shaw posted:

Thanks for all the help. I don't know what a triac is. But there is a brown wire from the mother board going to the smoke switch. Color changes to blue going back to the smoke unit. But I think I found the elusive problem. When I wiggled the input blue wire, I measured a drop in resistance (between blue and ground) from 27 to 10 ohms! The culprit is the white insulating sleeve that has burned thru - see photo. Ordered a new radio board today thanks to great Lionel parts supply.  But direct replacement  smoke units are not available. So I ordered a new smoke unit from a Camelback of similar vintage. The bracket is a slightly different in height. So some engineering will be needed. I have a new 27 ohm resistor by itself, but no way to replace the white (fiberglass?) insulating sleeve myself. It needs to be heat resistant.  Afraid that shrink tubing won't work.

I have a bunch of those stock smoke units for this loco....you may contact me if you want one.....

Pat

The sleeve is a mesh. Pressure on the lead can push it through an opening in the sleeve and make contact with metal cap. In some cases I have put shrink tube on the resistor lead then place the sleeve over it to prevent this from happening. You may have to enlarge the hole in the cap a bit to get everything through.

Pete

I'm planning to reuse the relatively new resistor because it has only 30 minutes of run time. Slipped on two layers of blue shrink tubing to the input wire. This fits snugly in the existing hole. Added a small piece of Lionel batting. See photo. Look ok? Waiting for the radio board from Lionel. As shown in the original post, the particular black component ( triac? )that burned up was bent outward to allow the radio board to fully seat in the connector.

Now waiting for a new Radio board. Should it need a reset? If a reset is needed, are there any quirks with using Legacy? I understand the procedure. The reset code on this engine is 74. But after I enter the new engine number and press Aux1 the screen changes from numbers to icons. Do I just press the corresponding icons?

When working properly, these old mechanical smoke units perform very well.

Resistor looks good. Just make sure the resistance stays at 27 ohms after you put the cap down. You will have to program the new radio board when you put it in. 

Pete

I just rebulit my 5433 version per Alex M's upgrade thread where he drilled out the intake holes, smokes very well for what it is to tie me over until upgrade time. (Alex M Great success with Lionel Puffer Unit)

The insulating mesh on my resistor looks brand new, the whole loco appears to have minimal run time.

My question is regarding the heat. The front third of the loco gets warm from the smoke unit. Is this normal? This is the only puffer unit I've had in command voltage. The smoke unit itself is the same temp, warm but not "hot".

My  newer fan driven units don't seem to warm the shell much, but I presume thats due to the fan pushing the heat out the stack.

Just want to make sure I don't end up with an issue like the O.P. had if I missed something rubbing.

BTW, what was the final outcome of this repair Bob? All fixed?

@RickO posted:

I just rebulit my 5433 version per Alex M's upgrade thread where he drilled out the intake holes, smokes very well for what it is to tie me over until upgrade time. (Alex M: Great Success with Lionel Puffer Unit)

The insulating mesh on my resistor looks brand new, the whole loco appears to have minimal run time.

My question is regarding the heat. The front third of the loco gets warm from the smoke unit. Is this normal? This is the only puffer unit I've had in command voltage. The smoke unit itself is the same temp, warm but not "hot".

My  newer fan driven units don't seem to warm the shell much, but I presume thats due to the fan pushing the heat out the stack.

Just want to make sure I don't end up with an issue like the O.P. had if I missed something rubbing.

BTW, what was the final outcome of this repair Bob? All fixed?

That’s how they are Rick,....remember, the puffer unit has its element a lot closer to the roof than a fan driven unit does....plus, with a fan unit, obviously there’s air circulating around it....biggest thing is the fan units sit lower in the chassis.....you’re just feeling the heat sinking into the casting....ain’t gonna hurt a thing....use it as an excuse to go fan smoke & four chuffs...😉

Pat

Thanks alot Pat! I really appreciate it.

  I really love this "old loco", I think I'm gonna wear out the whistle button on my remote LOL!  

Plus the other things ,like it comes apart and goes together easy.

From looking at it I swore there was detail from the shell that connected to the chassis somewhere, not so, And if you miss the holes in the pilot for the from handrails they don't immediately scrape the paint off, apparently paint application is also first rate.

@RickO....yep...totally agree....I own 7 of them....truly little battle tanks...now you need to find you the 28084 Dreyfus ....same loco mechanically as 28072 &38041 ( 38041 being the best of them)........

Pat 

Rick, not sure but I think they may have used a felt washer between the top of the  smoke unit and the shell just like post war engines. That helps insulate the shell from heat as well as help keep smoke fluid from running all over the inside. Even if Lionel didn't use one, you still can add one.

Pete