maybe nothing more than a dead battery?

Could be a bad smoke fan motor causing board to shut down at chuff.  G

Thanks G, I'll try and swap one out.

Joe, Unplug smoke fan leads  Turn smoke on and try again.  If it runs fine reinstall smoke fan plug and do heat element.  That should isolate it.  Do not run too long without fan motor running.   G

Engineer-Joe posted:

Again she'll run roughly without smoke, but shuts down or severely stumbles with smoke on.

Are you saying that it doesn't run right even without smoke on?

OK, forgive me as I did some last night and I'm back at it. So here's from memory.

With the smoke off last night and the engine running, she drew around an amp. With the smoke on, she jumped to 2.5 amps. When I turned the smoke dial back off, the engine sped way faster.

This morning I fired her up with the smoke unit unplugged and the smoke dial turned up. She drew something like .7 of an amp and ran good. Seemed to smooth out any binding or motor noise that I heard last night? Maybe she was struggling for power?

 I will try the smoke motor and element each as suggested later.

smoke filaments = 6 ohms

fan motor = 8 ohms ran good with 2 AA batteries.

Will swap out whole unit and/or look for shorts in wiring. Maybe another bad smoke pot?

Speeding and slowing when turning smoke on and off is normal if testing conventional as the load changes the voltage on the power supply does too.  G

Thanks again G. I thought it was more than usual. I'm jumpy because I don't wish to see the board fry. I was going to put my SD70ACe smoke unit in her as it would be a quick swap. I also thought of putting this board in that engine to see what happens.

 Life gets in the way and I can't work on trains anymore today. I have to do some honey do list stuff first,..... and second, third,...and so forth.

Here's my board test. The (O scale) smoke unit was chuffing fine but can't be seen clearly with the white fence in the background.

 I believe what happened, is the engine arrived with a dead battery. It had zero shut down sounds. I did not test anything first. I placed the engine on my RR with DCS on. I added the engine to the remote that changed the address to #1. That probably did not stick. The engine ran forward over an unpowered frog and sputtered. I am not sure why it stalled at that point.

 When I attempted to use the remote to restart the engine, it said "engine not on track". That is because the engine is supposed to be in address #1 but had reverted to whatever address the old user assigned. I attempted to then run the engine on straight DC, but with a dead battery, that's a crap shoot.

 She is drawing extra power in conventional with the smoke up full. I don't see any shorts with my meter. If I turn the pot down slightly while she runs on rollers, the engine behaves pretty well. I need to test further with DCS. I don't know if the pot is active in DCS mode at all? Maybe a shorting pot would still be bad for the circuit? It seems good with my meter anyways. I had one that shorted when shut off.

 The fact that some other person tore into the gear box and stripped most of the screws so bad they would not stay in, has left me guessing on why they were in there. I will have to test the engine now under some kind of load to see how she behaves. Please, if you go into a plastic engine, don't torque the screws so tight! A tip I learned here is to back the screws slightly at first until the screw finds the threads that are already cut. Then turn the screw forward until snug.

I will post more as I get time.

Did you get a new battery installed? 

Doesn't appear to need it. I charged her all night and now she has full shutdown sounds. I did load her into DCS again when the board was in the diesel. I'll see how the battery performs.