Athearn Challenger Again

[davefoxx]

Sending it back to Athearn again when I know my hurry is not their strong suit and 7 months is way to long to wait.  I'll think about it.   Doug   

@rgengineoiler, I'm not sure why Athearn took seven months to repaint your Challenger last time.  That certainly seems unacceptable, without hearing Athearn's side of the story, that is.  That said, the time that I sent something into Athearn for warranty work, I had it back within three to four weeks.  Just sitting on it and thinking about it isn't going to fix it or bring you a greater return on your investment if you do eventually sell it.  Send it back.

DFF

[woodone]

Doug- sending you a PM

[peteski]

I know you have to work on your average daily post count, but now you're just speculating.  The OP didn't mention anything about running through a closed turnout or a derailment.  In fact, he wrote that the Digitrax system shut down, and there's no indication that any other locomotives were fried.

I apologize for disappointing you Dave.  In my experience in trying to help people I have seen a wide range of descriptions of the problems: From very accurate description of what happened, and what are the exact symptoms, to very vague (as vague as "it won't run").  I also often see people say that "it shorts" when they really mean "the circuit is open" or "it doesn't run" (with no actual short).  I was basically trying to extract more info about the problem since the original post didn't really have all that much detail.  I often resort to Perry Mason tactics: askign leading questions.  Sorry that I annoyed you.  I'll try to be less helpful in the future. 

My speculation about a the short was to  possibly describe what could have happened inside the model (as I did explain), and not the kind of short that causes a voltage spike which could cause other decoders to "blow their settings".

Did we possibly get up in a bad mood this morning, looking for a fight to pick?

My profession is troubleshooting computer equipment (iSCSI storage arrays) and you'll be surprised how difficult is extracting good timeline of events or even exact problem descriptions from the admins who call in with the problem (and many of them work for Fortune 500 companies).  So I often have to resort to offering them some possible scenarios, so they can give me a better problem description.  And that was what I tried here.

The original  post stated "Athearn sure can't reliably accomplish this task.  I am about ready to sell it.  When you spend that kind of money on an N scale Challenger, surely it should preform.  I just don't know that I want Athearn to touch it."  I don't know . . . to me it sounds like Doug doesn't want to sent it back yet again. 

[robertjohndavis]

What is the solution to raise top speed? I have changed CV settings but two of mine still move sloooooow. Advice? Rob

[CRL]

You must have modeled a slow order board somewhere.

[mmagliaro]

What is the solution to raise top speed? I have changed CV settings but two of mine still move sloooooow. Advice? Rob

When you run it on its back on the workbench, does the front engine truck run?  Or only the rear.  If the front drive coupling is disengaged, then the front wheels are just "along for the ride" and they put drag on the engine.

Also, although this was only a problem with first-run Challengers (so I thought), motors were over-oiled, causing high carbon gunk build-up to get into the commutator slots.  The engine would run, but very slowly, drawing lots of current and making the motor get hot.  You'd need to see the motor, or at least measure the current draw, to get an idea if this is happening.

Folks... I know this isn't going to be a popular comment, but the way to fix these things (and any loco) is to bypass the decoder first and see what the motor and mechanism are really doing on DC.  The first line of attack should never be to start messing around with CV's.

[peteski]

When you run it on its back on the workbench, does the front engine truck run?  Or only the rear.  If the front drive coupling is disengaged, then the front wheels are just "along for the ride" and they put drag on the engine.

But if that happened, wouldn't the disconnect engine actually drag on the track (not just run along for the ride)?  These locos are worm-driven (like other N scale locos) and the stationary worm would lock up the rest of the mechanism.  Dragging engine should be very obvious to notice.

[mmagliaro]

But if that happened, wouldn't the disconnect engine actually drag on the track (not just run along for the ride)?  These locos are worm-driven (like other N scale locos) and the stationary worm would lock up the rest of the mechanism.  Dragging engine should be very obvious to notice.

Ah yes... You are correct.  It can't be just disconnected.

[propmeup1]

My two cents, I have two of the early Atheran Big boys that run pretty good. Not my best engines but i can't complain. I have one challenger of their's and it likes to stall but not to a dead stop. Just slows down almost to a stop then takes off again. sometimes the front drive set derails. Looks like it wants to climb off the tracks. There is less weight up front then in the rear so i'm thinking about removing the traction tires from the front.   I was going to send it to Atheran but after reading your seven month thing, forget it.

Anyway you may want to contact Top Hobby and ask about repair. They're in Webster, MA.   He done some sound installs for my older none DCC friendly engines and I seen he has a thing on cleaning your engines.

Keith

[mmagliaro]

My two cents, I have two of the early Atheran Big boys that run pretty good. Not my best engines but i can't complain. I have one challenger of their's and it likes to stall but not to a dead stop. Just slows down almost to a stop then takes off again. sometimes the front drive set derails. Looks like it wants to climb off the tracks. There is less weight up front then in the rear so i'm thinking about removing the traction tires from the front.   I was going to send it to Atheran but after reading your seven month thing, forget it.

Anyway you may want to contact Top Hobby and ask about repair. They're in Webster, MA.   He done some sound installs for my older none DCC friendly engines and I seen he has a thing on cleaning your engines.

Keith

Sorry if I'm beating a dead horse... but THIS problem sounds exactly like the clogged armature slots that plagued the early run Challengers.  Excess lubrication in the motor eventually found its way onto the commutator, where it mixes with the brush graphite dust from normal wear and forms a semi-conductive goo that fills in the armature slots.

The one I had here to fix for this had exactly your symptom.  It would run, then mysteriously slow to a crawl and then sometimes spontaneously speed up again.  It is simply the goo shorting out the commutator randomly, and just as randomly, burning off and letting it run again.   I had to clean out the slots with a toothpick point and wash out all the excess oil with alcohol... TWICE.  (I thought I had it the first time, but after a couple of days, more oil and junk collected in there again).  After that, it ran great and went on its merry way.

I think the derailing problem you describe is unrelated.

[propmeup1]

I'll check the motor and clean it up. I've only ever oiled the rods etc.. I purchased this used a few years ago.  I'll give it a looken at though, thanks for the input.

KTB

[mmagliaro]

I'll check the motor and clean it up. I've only ever oiled the rods etc.. I purchased this used a few years ago.  I'll give it a looken at though, thanks for the input.

KTB

Right.   This oiling problem was straight from the factory.  And sometimes, an engine can go for years without any trouble, then be stored in its box for a while, tipped the right way, and the oil will find itself into the commutator and cause the problem.  You can actually pull the shell and pry the top brush holder and brush out of the Athearn motor, and peek in there with a flashlight, rotating the armature by hand, to see how the slots look.  I was able to clean it right through that hole with brushfuls of alcohol and a toothpick to scrape out the slots, without pulling the frames apart, desoldering, or removing the motor.

Another dead giveaway... if you hook up an ammeter and leave it connected while you run the engine, see if the current jumps way up when it goes into one of these "slow down" modes.

[propmeup1]

I cleaned up the motor a few min ago. It really wasn't dirty at all. Removed the brushes both sides no problem. The engine looks very good inside and out from the time i got it.  I remember it ran good for awhile before this slowing down thing started about a year ago.   I pulled the motor out and ran it and there was no slowing down at all. Ran great.  It also only does this in fwd. reverse is perfect. Go figure, the direction I need it most you know.  Just wondering if it's the decoder. i was thinking about replacing both big boys and the challenger decoders but not just yet.    One other thing, the fast I run it the more frequent it slows down.

[peteski]

Just wondering if it's the decoder. i was thinking about replacing both big boys and the challenger decoders but not just yet.    One other thing, the fast I run it the more frequent it slows down.

I wonder if some component (either mechanical or electronic) heats up from the heavier current of running faster and results in the slowdown??
If you have a multi-meter and can run the model under DC (which it should be capable of doing), you could still do the current measurement to see if the slowdown is related to the current consumption.

Since you checked the motor's commutator and it appears clean (no carbon goop in between the segments?) and if problem is mechanical, then you would likely see the current draw increase as the model slows down (while the speed setting on the throttle remains unchanged).  Generally, a properly operating locomotive would draw less current the slower it runs.