Smoke unit fan not coming on at start up??

Jeff: Did you check to see if the fan impeller spins freely when you had the resistor PCB removed? I have the Sp equivalent locomotive from that time period and the fan should spin when power is applied. Maybe try removing the impeller and put a tiny drop of oil on the motor bearing area and see if that helps.....

Well, there are only a handful of things that would cause that.  First off, try running the fan motor on 1.5V from a single battery when the motor is cold.  If it won't run on that, replace the motor.  If it does run on that, look at the three components on the PCB, the capacitor is the top suspect, followed by the 5V regulator and then the diode.  All of the parts aren't much more than a dollar, so simply replacing everything is not a bad idea if the motor is good.

The only other suspect would be the wiring and smoke switch.   A long shot is the triac on the R2LC, but if that works normally and turns the smoke on and off, that isn't that likely.

Also loose impeller is a possibility.  That is the dumb unit, not much to it.  AC in feeds element, and also feeds the diode and 5V reg for smoke fan. Make sure solder joints not cold cracked, and also jumper trace is full.  Unless it uses to center rail feeds or a jumper wire in the harness.  G

I find a lot of loose impellers on MTH stuff, probably because of the dynamic braking tends to stress the friction fit more.  I rarely see them on Lionel smoke units.   Cracked solder joints are certainly a possibility as well, I certainly agree.

So, power it up this morning and bingo, smoke. Maybe sitting 16 years didn't make it happy?? I appreciate the comments, I'll keep an eye on it!

Engine now back to no smoke at start up and then 45 seconds later it will kick on with a huge plume. Going to pop the shell and take a peak.

If you've verified no bad solder joints on the three fan power components, replace the smoke motor.

gunrunnerjohn posted:

If you've verified no bad solder joints on the three fan power components, replace the smoke motor.

OK, checking the solder joints will be next.

I do hear the fan on start up, that's why I'm perplexed by the smoke delay. However, I will trust your expertise and replace if everything checks out.

If the fan is running, it could be the normal delay in heating stuff up.  Do you feel air coming out the stack right away?  If not, have you checked that the impeller is tight on the shaft?  Obviously, if the motor is running, all the components that power the fan are probably OK.  In that case, I'd be looking for poor connections to the smoke resistor, did you make sure those joints were secure?  All your photos were of the bottom of the PCB, what about the top?

Another point is to make SURE the resistor is not totally buried in the wick, it should be firmly in contact but have the top exposed.  Also, the airflow from the fan chamber should go over the resistor and out the stack, if you have material blocking the airflow, that will adversely affect performance.

This is really weird.  You rebuilt it and the stack or fan port is not overly blocked?  I would visually observe and watch the fan impeller spinning.  Sounds like it is working, but why building up smoke before it exits and operates normal is weird.  That usually is a blocked stack, even if just from a fluid add.  G

GGG posted:

This is really weird.  You rebuilt it and the stack or fan port is not overly blocked?  I would visually observe and watch the fan impeller spinning.  Sounds like it is working, but why building up smoke before it exits and operates normal is weird.  That usually is a blocked stack, even if just from a fluid add.  G

Hoping to pop the shell off today and take a peak. The fluid goes straight down into the unit. The slow start of the smoke is even after it has sat and I have not added fluid since the previous run. I'll definitely report back!

Maybe the motor is gummed up from sitting so long in the box, and it takes several seconds to break free. Might try putting a tiny drop of oil on the motor axle where it enters the motor and turning it a few times, might loosen things up.

OK, just ran downstairs and fired it up after sitting a couple days. Smoke came on quickly. Maybe the fluid bubble is the culprit after all? I use the Lionel funnel to get it "in" there, time to refill and add a little "puff of air" and see what happens!!

Jeff, I always give them a little "blow job" after filling, even with the funnel you sometimes get a bubble.

Once again the proverbial "operator error" has proven to be the issue. I added smoke fluid, gave it a puff, sorry I can't say blow job, and everything is fine!

Jeff T posted:

Once again the proverbial "operator error" has proven to be the issue. I added smoke fluid, gave it a puff, sorry I can't say blow job, and everything is fine!

Have used the computer duster compressed air cans for a light bubble breaking shot across the top of just filled smoke units to start them. Works especially well on layouts where you can't easily reach the equipment for a top down "whoosh" of air. Glad to hear your issue is solved.