Tomix and DCC

Considering many of us have had issues with running Tomix on DCC, I started thinking a bit what could cause the problems. I've had both good and bad experiences myself, my Tomix DD51 runs just fine with a Lenz Gold Mini DCC decoder. However, a Tomix EF510 which I converted for my father has already seen 2 fried decoders and now a fried motor.

Personally, I can't imagine that Tomix trains cannot be run on DCC, it just makes no sense. The motors Tomix uses seem to be pretty much the same as any other brand uses (and not just the Japanese brands either), and there's nothing that I can think of that could cause the issues.

That is, until I just saw Cap mention Tomix's Constant Lighting system. Is there a remote possibility that Tomix trains have some sort of additional bits and pieces to make Constant lighting work. Would that affect how the motor functions and possibly cause a DCC signal to mess up the motor? I really don't know if it has anything to do with it, but as far as I can see, the Constant Lighting is the *ONLY* feature Tomix has that no other manufacturer (I think) has, and as far as I know, not all rolling stock is compatible with the Constant Lighting system (hence the CL icon in the Tomix catalog).

Food for thought?

A good thought, but I think we've been down this road before. I've heard tell (I don't have a source handy, nor a CL throttle of my own—could someone check?) that some Kato trains will light just like the Tomix ones on a CL throttle—yet the Kato models don't seem to have problems with DCC. Which suggests maybe CL is a red herring. But, I'm not gonna shut any doors just yet, because CL is still the best candidate for explaining these failures.

So, that said. If I understand, any specialized circuitry for the CL system is in the lightboards—I certainly don't see anything in any of my Tomix motors besides the motor, nor in any of my Kato motors. But I have seen some pretty wacky lightboards—lightboards with more than just some diodes and resistors—in some of Tomix stock.

So, the CL hypothesis predicts that decoder failures will occur in models with CL lightboards. For example, my DE10 does not have CL lightboards (those are an after-market option), and indeed the DE10 runs pretty well with no failures (that weren't my fault). So far, anyway. When I finish converting my EF81, I will have replaced the lightboards entirely, so that would be a good test case too. However, the Yumekukan OSHI-901 I will soon convert with a function decoder clearly has a CL circuit—prediction: It should fail. I haven't gotten a decoder for it yet, though.

What about readers' failed units? Has anyone had a failure in, e.g. the motor car of an MU, where there are no lights?

My DD51 has CL actually, but I haven't run it long/often enough for it to be a good test case. All in all it had maybe 2 hours worth of driving.

The thing is, there has to be some reason why Tomix trains are being problematic, would be nice if we could figure out what that reason is considering many of us have quite a few Tomix items =)

Martijn: I presume you used a Lenz decoder in the DD51? An alternative to the CL hypothesis is that people are having bad luck with a particular brand or model, and that the failures just coincidentally happen to be in Tomix models.

I think, as a first step, it would be good to collect the details of instances of decoder failure. (Now I am channeling Francis Bacon…)

The DD51 has a Lenz Gold Mini yes.

The EF510 has fried 2 Trix Selectrix decoders and a motor.

I also have an EF65 with the same decoder as the EF510, but that one hasn't run much.

Great discussion guys! I hope you can come up with some solution because Digitrax has got to be tired of me sending back blown decoders.

How do the Micro Ace DCC conversions go?  I don't see them mentioned as much, but they have a pretty substantial catalog it seems.

I've converted 2 Micro Ace so far, both with a Selectrix decoder. They run on my father's layout, and have been running fine for many months.

I'll second Martijn's account on MicroAce. I did it with a Digitrax DZ123 decoder and it's strait forward. I haven't had any problems with that train. I have had problems with the Tomix trains.

I hope Mrpig, aka Gordon, joins in the thread, he has been successful with his Tomix train conversions.

My notes from various sources. 

Tomix's constant lighting (CL) overlays HFAC (High frequency AC--which is different than AC) on top of the DC power to the rails. You may have trouble with DCC if the decoder thinks the HFAC is a DCC signal and tries to figure it out.  Which exposes the decoder to the risk of damage and or burnout.

This works fine with the 3-pole open frame motors Tomix uses (and Pro Z uses too.)

My notes from various sources. 

 

Tomix's constant lighting (CL) overlays HFAC (High frequency AC--which is different than AC) on top of the DC power to the rails. You may have trouble with DCC if the decoder thinks the HFAC is a DCC signal and tries to figure it out.  Which exposes the decoder to the risk of damage and or burnout.

 

This works fine with the 3-pole open frame motors Tomix uses (and Pro Z uses too.)

But the HFAC signal is only overlayed when using a Tomix powerpack that supports CL I believe. Which would mean that if you use a DCC powerpack, the HFAC signal wouldn't exist.

What I was wondering is if there is something that Tomix did with the motor to filter out this HFAC signal, and which affects the DCC signal to the motor somehow as well (DCC signal to the motor is high frequency as well). It's rather unlikely though, since you don't really see any difference in motors between Tomix, Kato, MicroAce and even newer Minitrix, Fleischmann, Arnold etc.

I have had problems with both the 300 series and the Dr Yellow.

The 300 runs but I need to crank the motor up to step 5 or 6 to start it turning whereas the Dr Yellow just doesnt work at all.

It seems to me that the motor has trouble gettting started and at the first sign of trouble stop.

I have thought about this at length - after all, I have $400 of trains sitting there doing nothing on the tracks. I have three observations:

1. The Tomix motors come with a capacitor which we remove when we install DCC whereas Kato motors do not. This must mean something. My theory is that the capacitor is used to store up enough power to proved a initial "pulse" to start the motor turning and possibly to keep it turning.

2. When I have the motor free running ( i.e disconnected from the gears and drive shaft) it runs easily. The problems start when it is has a "load".

3. The Tomix motors dont have a flywheel and so that tend to stop instantly whereas the flywheel will keep the momentum up enough to keep the Kato motor running.

On this basis, I must disagree with Martijn's base premise that the motor are the effectively the same. In my opinion, the motor are different and require more power than the DZ Digitrax decoders will output.  I am not sure what power the Lenz decoders otuput. 

The capacitor is telling…it might also be used to filter and smoother the HFAC CL signal, so the motor gets a smooth DC signal. In which case, you might be right that the Tomix motors don't respond well to the pulse-width-modulation (PWM) signal they get from a decoder. In which case, the capacitor should be left in during an install, but not for the reasons you mentioned… hrm, food for thought?

Interesting, my EF81 doesn't have a capacitor on its motor, nor did the DE10.

I think you are on to something here, Alpine…

I have had problems with both the 300 series and the Dr Yellow.

The 300 runs but I need to crank the motor up to step 5 or 6 to start it turning whereas the Dr Yellow just doesnt work at all.

 

It seems to me that the motor has trouble gettting started and at the first sign of trouble stop.

 

I have thought about this at length - after all, I have $400 of trains sitting there doing nothing on the tracks. I have three observations:

 

1. The Tomix motors come with a capacitor which we remove when we install DCC whereas Kato motors do not. This must mean something. My theory is that the capacitor is used to store up enough power to proved a initial "pulse" to start the motor turning and possibly to keep it turning.

 

2. When I have the motor free running ( i.e disconnected from the gears and drive shaft) it runs easily. The problems start when it is has a "load".

 

3. The Tomix motors dont have a flywheel and so that tend to stop instantly whereas the flywheel will keep the momentum up enough to keep the Kato motor running.

 

On this basis, I must disagree with Martijn's base premise that the motor are the effectively the same. In my opinion, the motor are different and require more power than the DZ Digitrax decoders will output.  I am not sure what power the Lenz decoders otuput. 

Most Minitrix, Fleischmann etc. have a capacitor as well. I believe it's mainly there to remove any possible interferences on other equipment. Kinda like a lot of connection tracks (the ones where you hook up the regular transformer) have a capacitor as well.

With the European brands, the capacitors are usually removed. Older decoders specifically stated you HAVE to remove the capacitors, modern decoders don't seem to mention them at all..

That said, I believe I have Tomix trains that have a capacitor, but I also have some without capacitor. Some of those without capacitor are still marked as "CL" ..

Will need to look at it a bit more closely. With a bit of luck I'll have a bit of space soon-ish, I've started sorting out various things and packing them into boxes. 1 way or another I'll be moving in the next 3-4 months.

Excuse my ignorance please, all this DCC stuff is over my head  :-[ especially installing decoders, one question, when I build my layout is it worth to set it up as DCC at time of building or can I do this later once its finished and running (DC) without too much trouble? also, as tomix is a problem, what do you do with say the Dr Yellow or 300 that cant run properly? can they be run on your layouts as DC, is it switchable?

Thanks  :)

Jansen - I am going to start a new thread called, "DCC: Is it for me?" And pose questions there about what's involved in going DCC.

Jansen - I am going to start a new thread called, "DCC: Is it for me?" And pose questions there about what's involved in going DCC.

Gee you're full of great ideas!  8)

Excuse my ignorance please, all this DCC stuff is over my head  :-[ especially installing decoders, one question, when I build my layout is it worth to set it up as DCC at time of building or can I do this later once its finished and running (DC) without too much trouble? also, as tomix is a problem, what do you do with say the Dr Yellow or 300 that cant run properly? can they be run on your layouts as DC, is it switchable?

 

Thanks  :)

It depends on various things. If you build a layout now, you can always convert it to DCC. In its basic form, you only need to replace the transformer with a DCC command station, and install decoders in each of the locomotives. Most DCC command stations also allow you to run 1 non-DCC locomotive, but I can't recommend doing so.

If, on the other hand, you want to automate all or parts of the layout, or if you want to use a computer to control trains, you'll need a LOT more equipment, and the amount of wiring required is quite staggering =)

I made a few posts about basic computer control and how certain things work. They can be found here:

Chapter 1: http://www.jnsforum.com/index.php/topic,370.0.html

Chapter 2: http://www.jnsforum.com/index.php/topic,372.0.html

Chapter 3: http://www.jnsforum.com/index.php/topic,403.0.html

The video I link to in chapter 1 is especially a good indication of what's possible with DCC and computer control. The trains in the video are all automated, they accelerate and decelerate smoothly, certain trains don't need to stop at the station (express, freight), some stop occasionally. The period they stop can be randomized as well, etc.

Excuse my ignorance please, all this DCC stuff is over my head  :-[ especially installing decoders, one question, when I build my layout is it worth to set it up as DCC at time of building or can I do this later once its finished and running (DC) without too much trouble? also, as tomix is a problem, what do you do with say the Dr Yellow or 300 that cant run properly? can they be run on your layouts as DC, is it switchable?

 

Thanks  :)

 

 

It depends on various things. If you build a layout now, you can always convert it to DCC. In its basic form, you only need to replace the transformer with a DCC command station, and install decoders in each of the locomotives. Most DCC command stations also allow you to run 1 non-DCC locomotive, but I can't recommend doing so.

 

If, on the other hand, you want to automate all or parts of the layout, or if you want to use a computer to control trains, you'll need a LOT more equipment, and the amount of wiring required is quite staggering =)

 

I made a few posts about basic computer control and how certain things work. They can be found here:

 

Chapter 1: http://www.jnsforum.com/index.php/topic,370.0.html

Chapter 2: http://www.jnsforum.com/index.php/topic,372.0.html

Chapter 3: http://www.jnsforum.com/index.php/topic,403.0.html

 

 

The video I link to in chapter 1 is especially a good indication of what's possible with DCC and computer control. The trains in the video are all automated, they accelerate and decelerate smoothly, certain trains don't need to stop at the station (express, freight), some stop occasionally. The period they stop can be randomized as well, etc.

 

 

WOW! thank you very much, I'll have a look at those links now.  8)

Hi Guys, just been reading through this thread. All my conversions have only been on EMU's so I am sorry I can't shed any light on the Tomix Loco's. As Bernard stated all my Tomix conversions have been problem free. I used the DZ125 on the E4 & 923 and the M1 on the rest. The one thing I always do is cut down the motor contacts, I didn't want to take any chance that the pointy contact would poke through any insulation and touch the pickup rails.

The only time I have had drama (including Kato) has been the fault of slack maintenance on my part. The track and especially wheels just needed a good clean. Both times this has resulted in very jerky motion and I have even had instantaneous direction reversals uncommanded. Don't know how that didn't result in stripped gears or universals. I think the intermittent contact caused by the grime just confused the hell out of the decoders. They would also end up running flat out regardless of throttle setting or even programmed max speed. A good clean fixed it right up and exorcised the evil demons that possessed my trains.

The capacitor on most of the Tomix motors is just to help prevent interference to things like TV's and radios (mostly AM). A standard cap will block dc and pass ac. When a motor is spinning, the action of the brushes on the commutator creates AC electrical noise, the frequency of which is directly proportional to the speed of the motor. Remember how old power tools and slot cars used to create snow on the telly. Well anyway, the capacitor passes all this AC noise directly to ground without affecting dc operation.

For a capacitor to help with starting our little motors it would have to be a polarised type, usually either an electrolytic or tantalum. There would also need to be some control circuit to only connect the cap to the motor on start up or else it would never be able to store a charge. The other problem is that our trains change direction. Polarised capacitors have a nasty habit of blowing up when connected in reverse for extended periods, thus letting the smoke get out. And everyone knows that electricity is a myth, things run on smoke and wires are really just very small tubes to carry the smoke around. That is why everything always stops when the smoke gets out. ;)

My best suggestion right now would be to double check for intermittent shorts between pickup rails, motor contacts and chassis. Check every possible combination of these 3. I am sure we can get your Tomix trains sorted.

Also, I have only got 2 of my Microace trains done but so far so good.

mrpig, thanks for the informative post!

Well anyway, the capacitor passes all this AC noise directly to ground without affecting dc operation.

This sounds like good reason to suspect that there's something up with the Tomix motors that come with capacitors. Have any of your trains that you converted had this capacitor? Since the signal coming off the motor leads on a decoder is effectively AC, I wonder if some of Tomix's motors are somehow particularly sensitive to AC signals…is this even a coherent thought? I am pursuing this line only because, e.g., Alpine has time and again checked the other things you mentioned, and insisted that everything is clean, and nothing is shorting (and we trust him :D). Shorts are still a possibility, but now alternative explanations are beginning to look more likely, especially since others are having similar difficulties.

Alpine, you cut out the capacitors, right?

My motors are capacitor free.

Well I was going to suggest capacitor removal, but I see you guys are one step ahead. These definitely need to be removed for any decoder. As Capt said, the motor signal is basically AC (pwm as he also stated early on) and the capacitor will see it as such and overload the decoder.

I have done some testing withe 300 and doc yellow. My 300 needs the start volts (CV2) set to 25 before it will start to move at step 1. The Doctor will begin moving with CV2=2, but I would call it more of a lurch. They both behave a lot better after a couple minutes warm up. The older Tomix mechanisms are also a lot noisier. Kato is definitely much nicer all round, but they all do still work on dcc. Except the 400, still working out how I'm going to do the install on it.

I think the Kato motors are definitely better and am wondering if it is because the earlier Tomix are only 3 pole.

The Tomix motors also draw more current, especially when stalled.

The Tomix motors also draw more current, especially when stalled.

Well, that's interesting to know. Do you have numbers to share?

Alpine, I wonder if its possible your 300 or Doctor Plough stalled at some point (maybe not during that particular incident), and overloaded the decoder?

Well I was going to suggest capacitor removal, but I see you guys are one step ahead. These definitely need to be removed for any decoder. As Capt said, the motor signal is basically AC (pwm as he also stated early on) and the capacitor will see it as such and overload the decoder.

Hmm.. My father has locomotives with factory installed decoders and those still have a capacitor on the motor, so not all decoders by default require the capacitor to be removed ;) That specific locomotive is a Minitrix though, nothing Japanese.

All the older motors for all brands are only 3 pole. 5 pole is a fairly recent thing to add in N-scale for the European brands, although I wouldn't be surprised Kato (as well as Tomix and MicroAce) started with 5 pole motors much earlier than the European brands. Especially considering how long it took the European brands to start with flywheels, even in H0 ;)