Atlas MP15 HELP!!

[CaptOblivious]

Before you throw out the power pack, do make those voltage measurements if you can (a voltmeter or multimeter is a good tool to have in your box anyway), so we can absolutely certain your throttle is to (at least partially) blame. This is just me being cautious again.

[Barobutt]

Oddly enough I do have such a tool.  Not 100% sure how to use it or read it, it has a lot of settings, but i'll try to get some measurements. 

It's really loud too.  Moment you turn it on it hums like some street transformer.

[Howard1975]

This has been a very interesting mystery to follow, it's like watching a good mystery movie. There are some very good detectives at this forum, and just like in a Sherlock Holmes story, I'm confident this mystery will be solved.

 

Looking back at my particular MRC 501 powerpack (the one with a metal case), I'm not sure why it eventually went bad, but it did. My dad had bought the powerpack used back in 1984 I think, and it was fine for the typical HO locomotives we ran at that time. Cheap locomotives made in the 70's and early 80's from Athearn, Bachmann, AHM, Like-Like, etc. They all had the open frame motors common at the time.

 

When I bought a couple MRC Tech 2 powerpacks about 10 years ago, I stopped using the very old powerpack. I just kept it as a spare unit, but never used it again.

 

When I decided to test that old powerpack a few weeks ago, instead of putting out 16 volts, it was putting out over 25 volts! Talk about a failing transformer. Also the potentiometer inside was no longer working properly either. Anyway, it was safest to toss it into the garbage, instead of taking a risk.

 

There is always the possibility that your particular powerpack is putting out the proper voltage (around 16 volts), and not failing like mine. I'm curious what you find, when you test it.

 

As for your Atlas MP15, I hope it will get fixed properly.  I'm guessing it needs that chip inside to run properly. Sounds so weird to me, that an analog locomotive needs a microprocessor to run properly. I guess that is the only way they could get realistic speed control with that mechanism. I have never seen a light board with a microprocessor chip, until now.

 

Good luck,

 

Howard

[Barobutt]

So I borrowed a voltage meter or what ever from my neighbour and set my throttle to 10% and it read 17.8.  I set it to 50% and it read 17.8.  I set it to 100% and it read 17.8.   I guess what ever it measures doesn't vary (I don't know bout electrons!)

 

What does this mean?  The meter has a lot of other settings, is there something else I should measure?  Would 17.8 what ever's be the cause of my horrible performance?

 

My wife measured different sections of track and it varied from 17.1 to 17.8 depending on location. When she put it on pulse it was 8. Looking online it seems most all power packs say they're 18v, so my power pack is working pretty much fine then?

 

THEN WHY IS MY TRAIN GOING SO DAMN FAST?!

[inobu]

When you perform the test use the full setting that way the voltage is constant.

 

Inobu

[inobu]

This is how pulse works.

 

Remember when you were a kid and would tap your bicycle wheel to get it to spin. You tapped it at a constant rate and it would keep spinning, the harder you tapped the faster it would go.

 

This is what happens when the controller is set to pulse. The voltage stays the same but pulses/taps faster. The controller is tapping your trains motor with voltage. The interval between taps are called duty cycle. Your volt meter is just reading it as one tap because it is so fast. If you had an oscilloscope you can read in milliseconds and would see it .

 

When you set it to full. it just applied the voltage 0% to 100%. You want to see what it reads from 0 to 100. If it is ok you will see 0v 0% 4 volts 25% 8v 50% 12v 75% and 16v 100%. If it reads close to that then your controller is ok but remember a little n scale used 0 to 12v . your HO controller maxes out at 16V so it going to drive your Atlas Speed scale motor harder.

 

Inobu

[inobu]

It you want to see the train operate at a slow speed. Take a piece of track off on its own and connect a D battery + on 1 rail and - on the other place the train on the track and you will see the train creep along because the D battery is putting out 1.5 volts. There is now way it will take off with 1.5 volts.

 

Inobu

[Howard1975]

The old powerpack that I recently threw away was exhibiting the exact same behavior, except mine was leaking a higher voltage. No matter where I put the speed dial, it would always show around 25 volts. I'm not an electrical engineer, but I know powerpacks are not supposed to function like that. I tested my powerpack with the switch at the "full" setting, not the "pulse" setting. That will keep the pulse turned off, to get a more dependable reading.  I tested my powerpack with two different meters; an analog meter, and a digital meter.

 

When I tested my newer powerpacks, they tested as I expected. Turning the speed dial up made the voltage increase, just like it's supposed to. I tested both of my MRC Tech II, 2500 models. They are designed for N - G scales, and put out a max of 20 volts. I know that is way too much for N scale, but when I bought the powerpacks in the 1990's, I was running only older HO equipment, mostly Athearn. Anyway, when I tested my Tech II's, they both tested fine. At a speed setting of zero, I got zero volts. At a speed setting of 25 percent, I got the expected 5 volts. At a speed setting of 50 percent, I got the expected 10 volts, and etc.

 

Now I'm very curious how your Like-Like and Bachmann operate fine with that old powerpack.

[Howard1975]

My second posting,

 

  I should add, I don't remember the exact voltages from my Tech II 2500 powerpacks, it was a few weeks ago when I tested them, but they both tested fine.

 

I'll be shortly building a new layout, with Kato, Modemo, Tomytec and Tomix equipment --- and modeling passenger, freight trains and trams. I have decided to get another couple Kato powerpacks, since they put out a safe 12 volts. I know the 20 volts my MRC Tech II 2500 put out is too much for N scale trains. I can use them for something else.

[Barobutt]

I just went back and tested again.  I made sure to test in the exact same spot on the track every time.  At 10% power,  17.2,  at 50% power, 17.3, at 100% power, 17.2.  Pulse gave pretty much the same results with a constant 8.1-8.2

 

I put my nice life-like engine on.  I opened it up and it's from 1996 and has an open motor in case that's important.  On full it starts up a little fast, and smoothly ramps its speed up as I increase the throttle.  On pulse it starts at a crawl and gets up to an slightly above-scale max speed.  Nice.

 

I throw my $20 bachman steamer on and there's similar results but a bit crappier for obvious reasons.

 

Then I let the bachman just spin its wheels in a corner and I decide to test the track (on full not pulse) while a train is actually running.  My meter goes all over the place.  At 10% on full it jumps between 10, 12, 15 very rapidly.  At 100% power it jumps between 12, 16, 17, and 19.  Was I suposed to take these measurements with a train running?  Because only with a train running has my throttle influenced the readings in ANY way.

[CaptOblivious]

A throttle that shows variation in voltage only with a train on the tracks is either a bad design or broken. Shouldn't do that.

 

Here's what you SHOULD be seeing, to give you an indication of the degree of brokenness:

 

0% throttle    0V

10%            1.6V    =(10%*16V)

.

.

.

50%              8V

.

.

.

100%            16V

 

The voltage should ramp up smoothly with the throttle setting. But, some voltage regulators require a load to work, and your throttle seems to be like that, which is why perhaps a train has to be on the track. Put your MP15 on, and take some measurements. I bet you won't see much variation, because I bet the MP15 doesn't present much of a load to your throttle. Which, if so, would explain the super-fast behavior.

 

One thing's for sure: I can now easily recommend getting a new throttle :D

[KenS]

I just went back and tested again.  I made sure to test in the exact same spot on the track every time.  At 10% power,  17.2,  at 50% power, 17.3, at 100% power, 17.2.  Pulse gave pretty much the same results with a constant 8.1-8.2

 

I think your power pack is broken.  I have the exact same one, and while I avoid using it due to the voltage, it works fine for N-scale trains.  I was using it to run my Modemo trams for a time. At a low setting with the switch set to Pulse I've seen it put out an average voltage of 1.7V RMS, with the waveform peaking at 8V (I used an oscilloscope).  If you want to see some pictures of the output, see my DC Power Pack page (the "Old (c. 1970) MRC" power pack is this one).

 

For a replacement, the Kato power pack is a very nice one.  If you're not using Unitrack you'll need to cut the end off one of the feeder wires to connect to track with screw terminals or soldering, since the pack only takes their cable connector so you have to start with one of their cables.  But any modern pack used without setting the throttle to full should be safe.  A pack limited to a maximum 12V output (like Kato's, or Tomix) is most important if it may be used by kids who aren't likely to remember restrictions on setting it to full.

[inobu]

Baro,

 

 

When you are testing be careful not to mislead yourself. If you notice in all your testing results you explain the trouble followed with how good it was.

 

"I put my nice life-like engine on.  I opened it up and it's from 1996 and has an open motor in case that's important.  On full it starts up a little fast, and smoothly ramps its speed up as I increase the throttle.  On pulse it starts at a crawl and gets up to an slightly above-scale max speed.  Nice."

 

 

I throw my $20 bachman steamer on and there's similar results but a bit crappier for obvious reasons.

 

Then I let the bachman just spin its wheels in a corner and I decide to test the track (on full not pulse) while a train is actually running.   My meter goes all over the place.  At 10% on full it jumps between 10, 12, 15 very rapidly.  At 100% power it jumps between 12, 16, 17, and 19.  Was I suposed to take these measurements with a train running?  Because only with a train running has my throttle influenced the readings in ANY way.

 

 

but in all actuality all test conditions had faults. The best methods of fault isolation is to establish a known good scenario and inject the troubled unit into it.  

 

In any case I enjoyed this exercise.

 

Thanks and enjoy

 

Inobu

[CaptOblivious]

I'm a little suspicious of the image on Spookshow's site, that the board there isn't the stock light board. There is no  reason to use a PIC microcontroller, and designing a microcontroller for the model would drive the costs up pretty high. I'm wondering if the photo on Spookshow's site is of a unit with a factory-fitted decoder, and that the DC version uses ye old standard analog circuitry. Someone here said they had an MP15? Could they confirm for me that the stock DC version really does have a microcontroller on its circuit board? I can't find an image of the stock lightboard anywhere on the web (except for many copies of a photo from Digitrax's installation instructions that show a picture of the Digitrax decoder, misleadingly labeled as the stock board. You can tell that it's not, though.)

 

Hypothesis: It doesn't, and the PIC is a red herring. We've pretty much moved beyond that point anyway, but we still want to puzzle out the NIB mystery (probably another crappy throttle).

[Bernard]

I just have to say....this thread reads like a "really good murder mystery"

I look forward to reading it everyday. (I'm learning a lot from it.)

[Barobutt]

You guys want me to make a video on how my life-like and bachman run ?

[westfalen]

maybe it was his "mate" who changed the motor hahaha hence the dodgy wiring

I was thinking the same thing, I have a couple of MP15's that are good runners. If he's done so much messing around with it he might have changed the motor too, maybe not on purpose, I've damaged a couple of motors soldering leads onto the brushes (take them off first!!), he might have just used an older motor he had in his parts box. Even old Atlas stuff should run slower than that though.

[Barobutt]

Nah it's the stock motor.  We carefully compared it to the brand new mp15.  And besides, both my mp15 and the brand new one ran exactly the same.

 

I think the issue is more or less solved, but no where close to fixed.

 

The DCC issue is due to incompetence, miscommunication, or outright thievery.

The poor performance is due to an extremely old and probably faulty power packs in both tests.

[Guest ___]

I second the KATO power pack. I had and still have a very reliable tech II 2500 but since I use the KATO 3 light block signals I decided to go with he KATO and have no regrets. The only thing I miss is the momentum control.

 

I just went back and tested again.  I made sure to test in the exact same spot on the track every time.  At 10% power,  17.2,  at 50% power, 17.3, at 100% power, 17.2.  Pulse gave pretty much the same results with a constant 8.1-8.2

 

I think your power pack is broken.  I have the exact same one, and while I avoid using it due to the voltage, it works fine for N-scale trains.  I was using it to run my Modemo trams for a time. At a low setting with the switch set to Pulse I've seen it put out an average voltage of 1.7V RMS, with the waveform peaking at 8V (I used an oscilloscope).  If you want to see some pictures of the output, see my DC Power Pack page (the "Old (c. 1970) MRC" power pack is this one).

 

For a replacement, the Kato power pack is a very nice one.  If you're not using Unitrack you'll need to cut the end off one of the feeder wires to connect to track with screw terminals or soldering, since the pack only takes their cable connector so you have to start with one of their cables.  But any modern pack used without setting the throttle to full should be safe.  A pack limited to a maximum 12V output (like Kato's, or Tomix) is most important if it may be used by kids who aren't likely to remember restrictions on setting it to full.

 

[Barobutt]

http://www.blwnscale.com/Kato%20Power%20Pack.htm

 

This one?

 

Does it not have a pulse setting? I need to run my engines on pulse to get them smooth and slow, or is this throttle so superior that it doesn't need such things?

[Howard1975]

http://www.blwnscale.com/Kato%20Power%20Pack.htm

 

This one?

 

Does it not have a pulse setting? I need to run my engines on pulse to get them smooth and slow, or is this throttle so superior that it doesn't need such things?

 

Yeap, that is the correct Kato powerpack. Nope, it does not have a pulse setting switch like your old MRC 501, and to be honest, you probably won't need the separate pulse switch. I believe many of today's powerpacks have a built-in momentum (pulse type) feature, that starts the momentum stronger at slow speeds, and gradually decreases as you increase the throttle setting, and eventually outputs straight DC at higher speeds. But I'm not sure about the specifics concerning the Kato powerpack. 

 

Also, many of todays powerpacks have much more advanced circuity inside (they are often a board with computer chips) for smoother control, compared to your old powerpack.

 

Naturally, a modern powerpack cannot perform magic. Using a modern powerpack will not guarantee that every single locomotive you own will operate perfectly and flawlessly. You still need clean track, clean wheels, and good wiring (no short circuits, faulty soldering jobs, etc).  Also, please understand, a modern powerpack cannot turn a lemon into a flawless locomotive. If it used to shake, sputter, constantly stall, or derail, etc, it still will.

 

But if your locomotive is operating correctly, it will function even nicer with a modern powerpack. You'll have smoother and finer control. And you won't have the jack rabbit starts anymore. Your locomotive will operate more like the prototype, like it really weights 100 tons.

[CaptOblivious]

The Kato powerpack does in fact use a kind of pulsed power, albeit it different in quality than MRC uses—there's no switch, which means you can't turn it off :D See Ken's rather nice write-up and comparison against an older MRC throttle like yours:

http://www.sumidacrossing.org/SumidaCrossing/DCPowerPack.html

 

If you like the way your models behave with the MRC pulsed power, then you should probably consider a newer vintage MRC pack, I think. I have one of these that I use with our HO Christmas train, and rather like its feel; I could put it through my O'Scope and see if it uses pulse power (doesn't say):

http://www.modelrec.com/search/product-view.asp?ID=1290

[KenS]

Well, to be clear, what Kato is doing isn't "pulsed" power.  True pulsed power has taller pulses with longer gaps, and I believe that has an advantage over what Kato does (smaller pulses closer together), although you may get some of the benefit from Kato's approach. The effect of pulsed power is to overcome the tendency of DC motors to want to stop at certain points in their rotation due to the structure of the motor. This tendency can be magnified by mechanisms with a lot of friction, but is somewhat offset by newer motor designs that use skewed windings (true of all modern Japanese trains I've seen) or five-pole motors (used in Kato's pre-"DCC Friendly" designs). I wrote a post on my site about train motors a couple of months ago.

 

Pulsed power is more important with older mechanisms that aren't as free-running as a modern one (either poorer quality mechanisms, or ones which are in need of lubrication due to age). It can also be useful on dirty track or if poor/inadequate wiring causes significant voltage drops between the power supply and the track. But that doesn't mean it's useless on new trains. If slow-running on DC is very important to you, you may still want to have pulsed power. This is something I haven't taken a close look at myself, as I switched to DCC long ago.

 

The Kato pack is a good one, and works well, but if you really need pulsed power get one of the band-name power packs that specifically calls this out as a feature (I don't have experience with current DC packs, so I can't recommend a specific one with that feature).

[Barobutt]

I only like pulse because my trains go a lot slower, well my 2 trains. 

 

But this power pack I'm getting is pretty much for my CENTRAM (the cheap one, not the kato one) so that should narrow down the recomendations.  I think clearly the kato 12v pack would be the best for a japanese tram, right?

[Howard1975]

If you would like to read more about pulsed power, and how it relates to older and newer locomotives, I suggest you do a Google search. Just enter this exact phrase into the Google search engine: "MRC pulse power", without the quotes of course.

 

You should get some interesting results for further reading. When I did the search just now, the first link goes to another model railroad forum, but I'm not sure if I'm allowed to post the link here. It's from the people that publish the "Model Railroader" magazine, popular here in the United States and Canada.

 

You might also find other websites that are helpful for your decision.

 

I'll give you my personal experience and recommendation. Based on everything I have read, and the actual trains I have owned, I would recommend a modern powerpack (such as made by Kato or a MRC Tech 2 or newer) if you mostly operate newer locomotives, especially those made after 1980. By the way, it's fine if you want to operate older locomotives with an older powerpack, for nostalgic reasons. Like some hobbyists, that use 60 year old transformers to run their Post War (or even Pre-War) Lionel, Ives, American Flyer or Marx equipment. The same thing with those hobbyists that operate antique Marklin locomotives, with a Marklin powerpack made 50 years ago.

 

But if you plan to operate mostly newer locomotives, I would highly recommend getting a more modern powerpack.

 

Today's modern locomotives draw much less amperage, compared to the locomotives from long ago. The problem with trying to operate modern locomotives with an older powerpack, is the old powerpack was not designed to operate a motor that draws so little amperage. An old powerpack normally used a very simple device, a rheostat, to control the speed of the motor. Old motor designs needed more amperage to get the motor initially spinning, and to keep it spinning, because they had more resistance. Because modern locomotives draw less amperage to get going, compared to older locos, the simple rheostat is not efficient enough to smoothly control it.

 

A modern powerpack resembles a computer inside, with circuit boards and computer chips. Some of them are quite advanced. Only a DCC system is more advanced. Personally, I have been very pleased with my MRC tech II 2500 powerpacks, and my Kato powerpack. I would highly recommend either brand.