New N Spectrum 2-10-2 "pauses" when drive rods reach bottom on fireman's side

[Rusty Rails]

I have a new Spectrum 2-10-2 DCC with an annoying low speed trait.  It pauses - in both forward and reverse - when the drive rods reach the bottom of their "circuit" on the fireman's side.  Click this link to view a video of the problem - http://youtu.be/v8gajurBWuk  The hiccup disappears at higher speeds.  I have checked the driver wheel gauging and it is OK.  I have also checked quartering and there is no problem there.  My Spectrum EM-1 2-8-8-4 does not exhibit this problem.  In fact, it runs so smoothly and slowly I have to double check to see if it's really moving at all.  Neither do any of my Spectrum diesels show any signs of this pause, only the 2-10-2.  I checked for bent drive rods and there were two with very slight bends which I very carefully straightened.  No change in performance.  Anyone have any ideas as to the cause and remedy?

[gatrhumpy]

You're going to have to pull of the bottom plate and see if there is any gunk in the gears or anything like that.

[James in FL]

 Hi Rusty Rails,

I don't see anything in that video that jumps out at me.

I would start by turning the engine to that slow spot.
Then I would check, with the point of my exacto, for a minuscule amount of play in all your rods, everywhere they connect, check all your valve gear, anything and everything that pivots.
Check both sides.
If you don't find it there, then it's in the mechanism.
Be careful with the tender wires.
You may be able to see it with the bottom plate off.
Run the tip of your blade in each tooth of the driver gears, be sure the blade is all the way to the bottom, and wipe it off after every tooth.
If that does not find it, you're going to have to crack it open.
In very few instances, I have found a simple loosening of the bottom plate screws, and/or the frame half screws, will free the mechanism up.
If you haven't found it at this point, then open heart surgery is next (motor removal), followed with a clean and re-lube.



Keep us posted.

Good luck

[gatrhumpy]

Another fix: Turn the three screws to the plastic bottom plate a quarter of a turn. That should loosen up the binding.

[Rusty Rails]

My thanks to all of you who replied.  I would have responded sooner, but have been down with a respiratory infection.

I did pull the bottom plate off before I posted but didn't notice anything in a casual inspection.  After Xmas I will apply all of your suggestions in a much more thorough manner and report my findings.

So glad to have folks willing to help.  Seasons Greetings to you all! 

Rusty Rails

[James in FL]

If you’re not comfortable with DIY surgery, you could always send it back to Bachmann, it’s rather a new release, and would be either serviced or replaced.

Good luck

[spookshow]

It seems like something is binding someplace, and so far I like the screw theory (either too loose or too tight). In addition to the bottomplate screws, there are three screws that hold the chassis halves together -



I had a Bachmann 0-6-0 that behaved very much like your 2-10-2, and the solution to the problem was to tighten up the chassis screws a bit.

Good luck!
-Mark

[Rusty Rails]

Question: What do these three things have in common?  Water into wine, raising the dead, the "pause" is gone.  Answer: I guess they are all miracles.  The next question is: how are they accomplished?  And the answer is - I don't know.

I tried all the suggestions shown above and the pause was still there.  I tested after each "modification" and, each time, showed no change.  So I continued to examine, poke and prod.  At some point (the last round of poking and prodding, obviously), the pause went away.

It has either disappeared or is so unpronounced as to be unnoticeable to the naked eye.

I will put this one to bed - I am a happy hogger !

Thanks for all the suggestions and ideas.  I'm sure it was some combination of them that did the trick.

Rusty

[gatrhumpy]

Yay teamwork! (high five)