MTH Smoke Unit Does "NOT" Chuff...Blows steady Stream

Did you check to see that Proto Chuff is set to "AUTO" and then select a Chuff Rate?

Hello,  Yes, it in on auto.  I get the "chuff sound"...everything is working ok with the chuff sound, rate, etc...but the smoke is "not in sync" with the sound....it just blows out in a steady stream....like the old smoke units used to do.

You should be able to hear the whirring sound of the fan motor by putting your ear close to an engine smoke stack.  If you turn smoke OFF does the fan motor continue running?  If a noisy environment or poor hearing prevents you from detecting the whirring sound of a stuck-on fan motor, when you turn smoke OFF you should see the smoke stream continue but thin-out as the fan clears the chamber following the termination of smoke generation.

If the fan motor is stuck on, there are (at least) two possibilities. (1) a short in the wiring to the smoke unit, or (2) a short in the transistor that drives the fan motor.  (1) can be found by inspection. (2) requires replacing a tiny component.  Unfortunately (1) can lead to (2) so there is a logic to repairing this but one step at a time.

This wouldn't happen to be a PRR S-2 turbine would it? 

In reponse to the previous post, the Fan "is" turning on and off in response to the smoke on/ smoke off from the DCS remote.  When I first begin operation of the Locomotive it appears that the smoke is "trying" to puff as I can see the smoke building up in the stacks and almost "pulsing",  but not really pushing out....then wthin a few seconds, it blows straight up out of the stacks like an older non-chuff synchronized smoke unit used to do and stays that way until I turn off the smoke using the DCS Remote. The fan is turning on and off with the DCS.  I also tried a "Feature Reset" and a "Factory Reset" using the DCS but this made no difference.  The chuff sounds are fine, but the smoke is a steady stream..no "puffing action" in sync with the chuffsounds.  It is "not as S-2 Turbine.

Is this a production MTH engine (NOT an upgrade) and did the puffing work at one time?

If you change the smoke level between HIGH and LOW, does the smoke fan motor change its whirring speed?  If you have a variable transformer feeding the TIU does the fan motor change speed as you alter track voltage from, say, 18V to 12V?

In other words, as you've fiddled with this, is there any action that changes the speed of the smoke fan motor - other than it instantly stopping and instantly starting when smoke itself is turned OFF and ON via DCS?

Hello all, I have "solved"  the problem with the "non-chuffing" smoke unit and this is something that others may want to check out if they are having a similar problem.  My Son, who is a computer IT person and also very good mechanically, (repairs old appliances, sweepers, motors etc as a hobby), checked it for me. We shut the sound off so he could hear the fan motor running. The motor was turning on and off during the chuff cycle as it is supposed to do, but he "heard" a difference in the rpm noise of the motor...something my hearing could not detect. What was happening was the fan "impeller" had worn itslf loose on the fan motor shaft and was "slipping" when trying to puff out the smoke during the repeated on-off cycles of the chuffing sequence. When the locomotive was standing still, it would spin the impeller properly and blow the smoke straight out, but under the constant start and stop cycle of the chuff sequence, the impeller would "slip" on the shaft and not push the smoke out in relation to the chuffing.  A very good cleaning of both the impeller itself (in alcohol), and the fan motor shaft, and a few drops of super glue in the impeller hole before placing it back on the fan motor shaft "corrected" the problem and now it "puffs away" in time with the locomotives "chuff". A word of caution though if you try this repair....be sure to turn the fan motor "upside down" when gluing the impeller back on the shaft so that no glue accidentally runs down the motor shaft into the motor and "glues the motor shaft to the motor itself.  Thanks for all who responded with your ideas.  I am "closing" this thread..."problem solved". 

One issue with the superglue.  If you ever need a motor replacement, it'll be a lot harder to get the impeller off to replace it.

A better fix is to chew up the motor shaft a bit with the jaws of pliers.  When you push the impeller down on the shaft, the shaft will cut into the plastic of the impeller and hold it tight.

The super glue does work and just about everyone who is out of impellers has used it.  I have done that also.

Impellers are very cheap and fit both MTH and Lionel smoke units.  I buy a handful every York from Jeff.

PRREnola, good post and this works with Lionel and MTH.  Your Son did good on the pickup.

Thanks all, and "Thank you Marty" for the compliment for my Son. Yes...he did do a great job of diagnosing the problem that had me stumped.  All suggestions are good for re-attaching the impeller to the motor shaft.  I "thought" about using heat but was afraid I might "distort" the impeller somehow.  I'm going to do as Marty suggests and pick up a handful of both replacement motors "and" impellers.  Marty, can you refer me to the person you were buying your parts from..?  Thanks..!

I am not home for a few days.  Hit me the middle of next week as I have a list on the desktop of my home PC.  Tell me what you do mostly as Lionel does list a few impellers and I can point out what you need.  One thing to note is as follows.  Whenever you push an impeller down over the motor shaft, hold something against the bottom of the smoke fan motor to prevent it from coming apart.  Those smoke fan motors were not made in America by union workers.  They come apart very easy.

Thanks Marty...I'll be in touch later in the week.

One way to diagnose this is with the shell off and smoke unit visible.  Normally when the impeller is loose like this you can almost count the blades as it rotates.  G

George, I like to let my finger very lightly touch the rotating impeller.  If I get a sting it is OK if it stops it is not.  Sounds very crude but it works.

Marty, You don't work on electronics that way do you....:-)  Hope your enjoying the nice weather in FL, Wave as your flying overhead on your way north!  G

George, it works.  Any looseness on the impeller will stop it cold with your finger.  Back home today.  It was hot when I left and 35 degrees when I got home.  Train season is now in full swing.  Big weekend at Charles Ro plus some layouts to see.

Not really.  CA has excellent tensile strength, but pretty poor shear strength.  It should pop right off.

I'll pass on the superglue anyway, I've had some where I wished I didn't use it.

I'm wondering if my brand new Baby Blue Comet has an issue related to this.

Before I start, I've had Railking steamers and I know how they smoke, so I do have points of comparison.

My blue comet needs to be set to HIGH to make it smoke like my RK steamers did on MED.  It smokes/puffs very well at a chuff rate of 2 up to about 35 SMPH.  At 40 SMPH I have to look real hard to make sure that it's still smoking.  Bring if back to 30 or 35 and it puffs away again.

Do you guys sense this is a similar situation?

(BTW: I don't feel like I'm stealing his thread since the 2 seem related)

thanks - walt

Walt, you might want to open up your smoke unit and take a look.  I have seen some recently with hardly any wicking. 

Thanks Marty, I'll do that.

Right now the only OTHER things I can think of, since both are new to me, are:

1. It's tin-plate and maybe that's normal.

2. It's PS3 and maybe that's the "new" way.

- walt

Walt;

I have a PS3 Steamer and it smokes the same as my PS2 units.

Can't give input on Tinplate.

Thanks for that confirmation Russell.  Have to eliminate all options.

- walt

Tinplate has the same electronics and smoke units, so I can't imagine them operating any different than any other PS2/3 locomotive.

Thanks for that bit of education!

Looks like I'm back to Marty's suggestion.  Will do that when it's time to pack up the Christmas layout for storage, since I clean everything first.

- walt