Atlas MP15 HELP!!

[Barobutt]

It still had the shrink wrap on it!

 

Why does my Life-like GP38 run perfectly smooth?  On full it runs pretty slow, slow enough that I'd be happy.  On pulse it runs ridiculously slow only stopped by my poor track and the odd-turnout where it loses power.  It also stops and starts slowly, like it has a good fly-wheel.  Both atlas mp15's stopped and started on a dime...  are you telling me a ~8-10 year old $40 life-like gp38 has a way better motor than a $120 atlas mp15??  

 

You guys have me so confused with all the conflicting info though. DCC can slow it?  My power pack might be too old/powerful?  Could my life-like eat tons of power and my atlas be over-sensitive??  

 

My wife says I need to be tough with the guy, contact him every week or so to see if he's fixed it and if there's no progress, demand a refund.  I'd take store credit too!  He's got a bunch of adorable little switchers, but you bet I'm going to test them before I buy them!

[keitaro]

i can solve the problem for you

 

take the train to the store stick it up the sellers arse and buy a different one else where :p

[Barobutt]

I bought it second hand almost a year ago.  What, am I supposed to take him to small claims court or something?  In which case it's him saying "It's second hand, he got it a year ago, now he wants his money back???" and me saying "but you promised it would run smooth and the DCC worked!" and him saying "I don't remember that, I sell all my second hand stuff as-is"

[keitaro]

chill mate i was joking 

 

it does however look like you have 2 choices replace the motor with a different one or sell it or keep it for spares. You could always re wire it, I just went through that with my kiha 130 tomix although it was 2 prongs and gluing the internal needle that gets the power.

alot easier than that looks....

[CaptOblivious]

I don't think anyone is doubting your throttle—no reason to yet (What is it, by the way?). It's hard to find a throttle that treats only select locos badly, and the rest well, you see. A bad loco will run bad on every throttle; a good loco will only run bad on a bad throttle. You have a good loco running bad on a throttle that treats bad locos well. Very confusing. But that means your throttle is probably just fine. The problem is the loco.

 

Inobu and I are engaged in a debate as to whether a good decoder can fix the running problems. That could be confusing, yes. I'm taking the more conservative route, and he's more optimistic. I do not yet know which of us is actually right.

 

There are some genuinely confusing facts, though, namely the inconsistency between your observations of the NIB MP15's behavior, and all the reviews. Which is not to say anyone is doubting you! Not at all. But I think everyone is confused by this. Because that shouldn't happen. Unless the throttle your dealer was using was shit. Which it might be. In which case, every loco put on it will behave similarly badly, and any differences between yours and a very nice NIB MP15 will be obscured.

[Guest ___]

Features (used where appropriate per road name):

 

   * Three different hood styles (standard air filter, square air filter box, angled air filter box)

   * Exhaust stacks: with or without muffler

   * Long hood sand fill: recessed or extended

   * Rear sand fill: Three variations of sand boxes behind cab

   * Pilot: standard or with snow plow

 

Standard Features:

 

   * Golden-white LEDs

   * Separately-applied roof detail

   * Painted safety rails

   * Directional lighting

   * Blackened metal wheels

   * Scale Speed™ motor

   * Factory-installed AccuMate® magnetic knuckle couplers

   * Many different railroad-specific details

   * Separately-applied coupler cut levers

 

What exactly does a "Scale Speed motor" entail?

 

PS: A somewhat related thread on my American train forum: http://www.trainboard.com/grapevine/showthread.php?t=57740

[keitaro]

max speed locked to units specs I would think in scale of course.

 

 

i'm pretty sure it's scale speed wouln't be 0 - 100km/h in .01 seconds ahahah

[Guest ___]

Maybe the model is related to Super Train and has ties to NBC?

[keitaro]

u sure this ain't a maglev with warp drives installed

[Guest ___]

Whatever it is, it's become a rather long thread on a foreign locomotive. Regardless, it is a bit of a mystery. What we need is the Matlock of model railways to solve this one.

[Barobutt]

new info from another forum I frequent (it's more about model buildings and way less active) is that perhaps the train is acting up because I'm using an ANCIENT HO-scale power pack.  The power pack at the store was HO scale as well.  I was told that my old(ish) life-like engine maybe just handles the power a little better while this state of the art atlas is a little more picky and doesn't need all that power.

 

Here's a pic of my power pack... don't laugh...

 

 

His throttle was also marked "HO" and was of a similar vintage... 

 

So why do my lifelike and bachman run so smooth?

[inobu]

lol that is it.

 

If your max voltage is 16v that means 50% throttle is 8 volts.  8 volts for N scale is about 96% throttle on a 12v controller. So if you do the math 25% throttle on your HO unit

is 4 volts on a N scale unit the throttle will be operating at 33% throttle. Add the Speed Scale motor and you have a rocket switcher.  

 

Inobu

 

Here is the comment I struck out

I'm a little perplexed about the speed problem but logic states if this is a plain DC configuration with no decoder then the excessive speed is from the controller. If he still has the controller set to pulse at the voltage setting is high along with the duty cycle then that is the culprit. DC speed is based on voltage and there is nothing in the cab that will step up the voltage so the only other possibility is the DC controller.

 

 

This was fun.

[inobu]

You should never run that controller more than 75% throttle for a N-Scale unit. 75% is 12 volts. 12 Volts is 100% for an actual N Scale throttle.

 

Inobu

[keitaro]

actually it looks like 20v ?

[inobu]

actually it looks like 20v ?

 

It's 16vDC and total 20VA (volts-ampers) which is the current rating. I tell you what, let one of those little N scale trains short that unit out and it will be the last time it does it.

 

 

Inobu

[Barobutt]

Ok, I'm going to scrap this thing.  It was given to me for free when I was about 12 years old...

 

I'm going to need to buy 2 power packs.

 

!!!WARNING: JAPANESE TRAIN RELATED CONTENT PAST THIS POINT!!!

 

Since I'm going to be running a tomix tram, what sort of power pack should I get for the smoothest slower operation?

[Howard1975]

Ok, I'm going to scrap this thing.  It was given to me for free when I was about 12 years old...

 

I'm going to need to buy 2 power packs.

 

!!!WARNING: JAPANESE TRAIN RELATED CONTENT PAST THIS POINT!!!

 

Since I'm going to be running a tomix tram, what sort of power pack should I get for the smoothest slower operation?

 

Hello sir, I have been following this on the sidelines, I think I'll chime in with a couple of questions.

 

What kind of powerpack does the store owner have? Is it an older powerpack like the one you have, or something newer?

 

I used to have one of those old metal bodied MRC packs, very similar to yours. I no longer have it anymore. I recently threw it away, because it was acting up, so I no longer trusted it. When I tested it with a multimeter a few weeks ago, it was putting out much more then the stated 16Volts. It's also what I got started on in the hobby, when my dad bought it maybe 25 years ago.

 

It's no comparison to my newer MRC Tech 2 powerpacks in smoothness or slow speed control. I also own a 1 year old Kato powerpack, which is also very nice. My Kato powerpack and both of my MRC Tech II's operate all my N scale (and HO scale) locomotives very nicely. Far better then that old MRC 501, which was not really designed for todays locomotives. I think that MRC 501 throttle was designed back in the 1950's or 1960's, back when most locomotives had open frame motors, which needed much more current.

 

Naturally what you decide to do is your choice, it's your money. But since you have decided to get new powerpacks, and you have a Tomix tram, my suggestion would be a Kato powerpack, which is designed for todays N scale locomotives. Assuming you live in North America, Kato makes a power pack specially designed for our 120 Volt electrical system. Or perhaps you could get a Tomix powerpack, which have the same electrical plug as 120 Volt North American, but are designed to operate on the 100V Japanese electrical system. Hope I did not confuse you there.

 

You could also purchase a newer Tech 2, or Tech 4 powerpack from MRC. It's your choice. Good luck.

 

Howard

[David]

I'll make one word of caution, just buying the digitrax board will not solve things. From what I can see a lot of the original parts are missing - I know from the experience of installing in my own MP15 that most of the fiddly lighting bits for the cab are missing on the one you have (even with poor photos the light pipe comes all the way down, and there is a big black difficult-to-get-placed-once-you-take-it-out light shield that rests on the frame. The motor clips are also very small and fragile, so I have my doubts that they've come through ok - I found the board is a difficult fit before you have to worry about motor contact (as is the case with a lot of Atlas engines where the frame/lightboard thickness varies from run to run, making a standard DCC board never give a perfect fit).

 

I did check last night but I can't remember where I stashed the original DC board for mine, that could give a clue if Atlas's 'scale speed' or 'slow speed' motors require a resistor or other bit to work as advertised (like how the little motors in the Kato Portram can't take straight 12V DC, they've got a circuit inbetween). I'll try again tonight.

[David]

A quick jump over to John spooks website has confirmed my suspicions. That's definitely the original DC board in his pictures, and you can clearly see a microcontroller on the light board. I think it's obvious that Atlas's 'scale speed' motors are not magical motors that can run at really low speeds without stalling, they're motors that run fast even at low voltage (normally a bad thing), coupled to a $0.75 microcontroller that sends pulse power to the motor based on a voltage meter (this is how a DCC board typically works when in DC mode). Personally I think this is a really smart idea (finally someone in MRRing realizing that cheap computers can do the same job as a complex analog circuits). Without the chip you're left with a motor deliverately chosen for it's jackrabbit qualities.

 

http://www.visi.com/~spookshow/atlasmp15dc.html

[Barobutt]

Then how come the brand new out of the box mp15 ran exactly like mine did missing a chip?

[David]

I have no idea, but I do know my new out of the box MP15 ran just fine at slow speed long before it was upgraded to DCC, and that microcontroller with assorted voltage regulation circuitry is certainly doing something (the whole board is very complex compared to other manufacturers DC boards - Kato's DC boards are practically just tin strips on the lightest PCB available with 2 LEDs and a resistor).

[CaptOblivious]

Hey, there is a PIC microcontroller on the stock lighting board! Holy cow, that explain a few things, you are right.

 

Let me just add that the fact that Barobutt's throttle is for HO, and puts out a max of 16VDC is a red herring. Howard is right to wonder what the actual voltage being put on the rails is, though. Could you measure that for us? At the lowest throttle setting that will move your MP15? And again at the hobby shop, if possible? Because that might explain why a NIB MP15 is acting weird.

 

But if your throttle is putting out a reasonably small voltage, and the MP15 is still rocket-like, then I wouldn't blame the throttle at all (just don't run it too hot!).

 

Finally, a proper DCC conversion, David is right to point out, still will probably need a new motor (with unmodified tabs), light pipe, etc.

[Barobutt]

When we opened the brand new mp15 in the shop it had its original light board, still ran exactly like mine.  In fact that's why we opened it up, to see what the DC board looked like as he had the same theory as you guys (that even the DC version needs some sort of board to run correctly).  We then put a random other engine on the track and it ran pretty smooth though, that's what confuses us.  Why is only the mp15 being fussy about the power pack and not other locos?  I guess we'd need to do more testing to really nail it down.  I just don't understand why my lifelike runs super smooth and both mp15's we tested run extremely jerky and fast on the same 2 HO power pack's

 

So I think there's only 3 options:

•There's some bad batch of DC atlas mp15's that run super fast

•The atlas mp15 doesn't like HO power packs to a degree much worse than other locos.

•Any new loco would run jerky on these 2 old power packs, and my lifelike and the random old shop engine were just flukes that run smooth on them.

[inobu]

It is the combination of the HO controller which is running 25% hotter and the motor. Just like Kato's move to 5 pole motors Atlas upgraded their motors.

 

The only basic principles to look at is applied voltage, motor efficiency and gearing. Looking at the NIB unit if it was opened from the wrapper then that gives us the basic OEM unit. There is no step up circuitry to increase voltage, the units speed is based on applied voltage and gearing. The duty cycle of the HO controller is unknown which one would assume is different from a n scale unit.

 

Apply 25% throttle on a 16v controller that is 4V or 33% of a 12v controller tie in the HO duty cycle with a efficient motor and it makes sense. Apply 1 volts to the motor and you will see the unit creep. I doubt if that controller could get 1 volts out. It is based on the potentiometer and its steps. If the points are worn then the output voltage could possibly increase. 

 

Inobu

[Barobutt]

So I think we got this wrapped up. The horrible DC performance is due to using an old HO power pack, the whole decoder issue is due to SOME DUDE RIPPING IT OUT AND TAKING IT.

 

I'll get a new power pack (well 2, one for my train, one for tram) to solve the DC performance issue

And I'll keep following up with the shop owner to make sure I get my chip back and correctly re-installed installed.

 

Depending on how it runs on my DC track on a new power pack I'll either keep it or sell it.  I think I no longer have interest in DCC, I just want the chip back for re-sale value.