Tomix 115 Running Jerkily

[scott]

I've gotten a couple of used engines to run more smoothly with a bit of cleaning and some oil, but for some reason my "NOS" Tomix series 115 EMU is having a lot of problems. I set up a test loop with some unneeded EZ-track, and am trying to get it going. Even after some oil and some running-in time, it still slows or stops (or is reluctant to start) in a fairly unpredictable way. The wheels look clean, so I'm trying to avoid using the 91% isopropyl alcohol for fear of messing up the finish. I can't see any gunk in the gears.

 

Is there anything else I should try, other than just more running-in time?

[alpineaustralia]

Is it DCC?

[Bernard]

Scott  - I don't know if this will help but have you checked the motor brushes? Since this is a used engine, the brushes can get worn down and effect the performance of the engine. Checking the brushes can be a little tricky so clear out a space on a work area, the brushes are very small and can easily pop out and get lost.

It's not a fun thing to do but it's worth looking into.

[scott]

Alpine--nope, it's DC.

 

Bernard--I'm not sure if it's used or not--it certainly doesn't *look* used, which is why I'm confused. But no, I haven't checked the brushes, mostly since I have no idea how.  :-[

[Bernard]

Scott - Lets try this before taking apart the motor to get to the brushes. What I do is take off the shell of the train and remove the motor from the chassis. There will be two leads on either side of the motor, take the 2 wire from the transformer and touch the motor. Is it running strong or weak? (this will tell us if the brushes are worn or if it's another problem) I'll wait for response...or if any other members have a recommendation for testing your problem.

[scott]

Thanks, Bernard--I have a bad cold and have a busy week coming up, so it may take me a while to get to this, but I'll definitely try it.

[SubwayHypes]

yes i too am having problems on some of my motor cars, my e217 motor is so crazy, it will sit there doing nothing then BOOM off it goes running fine.

 

i too have limited knowledge in how to take apart these cars and fix them, someone on JNS should start up a mailorder fixit business so we could mail our motor cars to you to fix!!

[Martijn Meerts]

yes i too am having problems on some of my motor cars, my e217 motor is so crazy, it will sit there doing nothing then BOOM off it goes running fine.

 

i too have limited knowledge in how to take apart these cars and fix them, someone on JNS should start up a mailorder fixit business so we could mail our motor cars to you to fix!!

 

 

 

I've been considering doing something like this for decoder installs and such as well. Nothing big-scale, just a little something on the side. Then I remembered that there are such thing as guarantee that something works and the fact that people might send in (semi-)rare / 1-time only models to be converted. And well, I don't want the responsibility of ruining those models ;)

[Bernard]

Martijn - Here is my feeling about this. There are some members here that are excellent at decoder installs/fixing trains, and you are one of them at the top of the list. I myself am not up to your level.

 

There are times when I can't fix a train and it's either going to be used for display or parts. Someone like you who has the knowledge, most likely can fix that train (or install a head & tail light decoder on a train) and have it up an running.

 

In the case of a rare train, I would have the potential customer explain to me what the problem is and then decide if I want to take the job on, and stress the point that there are no guarantees. (I still can't figure out how to install a decoder in the old Minitrix stream engines made in the 80s & have blown 2 decoders in the process)

 

So to sum it up: Martijn, I would rather take the chance and have you install a decoder on my Minitrix Steam Engine than have it sit in it's box never to be run.

[Martijn Meerts]

I've blown my share of decoders and motors as well. And it's fine if it's my own decoder or motor. It felt a lot worse when it was my father's train that had issues though.

 

If I were to work on installing decoders / repairing trains for others, I'd first have to come up with some extensive legal disclaimer =)

[SubwayHypes]

what about basic motor cars?  I have a 651 series motor car that is sqeaking like crazy, maybe it just needs  a little oil though.

 

if i could read japanese i would definately try to decipher the booklets and fix it stuff.

 

are there any english "how to" books on model trains so i can learn how to do this?

[Martijn Meerts]

Sqeaking might be solved by adding a couple of drops of oil around the motor axles.

 

 

One problem with many of the newer (and cheaper) trains, is that the motor is pretty much closed, you don't even have access to the brushes anymore, so cleaning or replacing them isn't really doable.

 

As I've mentioned before, I have very little space at home, not even enough to work on decoder installs and maintenance/repairs. Once I get some space though I'm hoping to do some reports with pictures/videos on various things. There are a lot of people who are much better than me, but none of them model Japanese prototype ;)

[scott]

Scott - Lets try this before taking apart the motor to get to the brushes. What I do is take off the shell of the train and remove the motor from the chassis. There will be two leads on either side of the motor, take the 2 wire from the transformer and touch the motor. Is it running strong or weak? (this will tell us if the brushes are worn or if it's another problem) I'll wait for response...or if any other members have a recommendation for testing your problem.

 

Bernard--

 

Thanks again for the idea. This turned out to be really easy--I didn't even have to take the motor out of the chassis, since there were two contacts visible through the chassis. It looked like they were designed to be used for testing.

 

Anyway, the motor ran great this way--absolutely smooth. So I guess the problem must be in the trucks somewhere. Any ideas?

 

Thanks!

 

scott

[Bernard]

Okay Scott the motor seems fine. Lets try this experiment. There are 2 drive shafts on each side of the motor connecting the motor to the truck gears. Be careful and don't lose it because they are small, remove only one of the drive shafts from one side and see how the train runs. Okay repeat the procedure to the other side.

This might determine if there is something wrong with one of the truck and which one.

 

(**I'm assuming that the Tomix train is using drive shafts but some of the older models use worms.)

[scott]

Thanks; that makes sense. There's a gray cover over the chassis with lots of clips that attach it to the chassis. I assume the driveshafts are under that. Anything I should know about how to get that off, or things to look out for?

[Bernard]

Scott - Here are 2 photo for you to look at but I would like you to post a photo of what you are talking about in your previous post.

 

The 1st photo is a Tomix chassis and you can see the tabs on the plastic piece that connect to the chassis. You take a small screw driver and pry them of the chassis but be careful, they can break. This Tomix train uses a worm to drive the gears in the trucks.

 

The 2nd photo is the underside of a Kato train and the gray thin rod is the drive shaft, it's what connects the motor to the gears in the trucks, this is what I'm hoping you train looks like.

[scott]

Thanks--that top one looks a lot like what I have.

 

But I tried checking the trucks by just running the motor as before (with wires touching the contacts on the  motor), and all the gears and axles turned just fine. It didn't look like one was running slower than another.

 

So I'm guessing it's some sort of conductivity problem from the wheels to the motor. (Thanks for the reintroduction to the scientific method.  :) )

 

BTW--after you replied, this thread wasn't marked "unread" or listed in my "new replies" list. Just thought I should mention it.

[scott]

I worked on this one last night for a while, and checked it over with a circuit tester. So far:

 

* With the chassis cover on, the powered car does not start. It occasionally moves a tiny bit with a shove, but otherwise nothing.

* The motor works fine by itself when power is directly applied

* Power is coming through the trucks to the springs that take power to the leads in the chassis cover (although it's a little easier to make contact at one end than the other with the circuit tester, but I'm not sure that means anything--the power is there)

* If I connect the transformer to the circuit paths on the chassis cover where the trucks would make electrical contact, the circuit tester shows that power is coming through

 

So it seems like power *should* be getting to the motor, but it isn't. Right now, I'm out of ideas, but I'll fiddle with it more tonight, time permitting.

[CaptOblivious]

So, it sounds like the problem is somewhere between the springs and the brass rails on the underside of the chassis cover? Or do you think the problem is between the brass rails and the motor tabs? At any rate, this seems a clear case of electrical contact failure (I feel pretty confident in calling this one ;) ).

 

Some considerations, coming from someone who doesn't own a Tomix EMU (so take them with a grain of salt). The springs in the trucks, when installed in the chassis, poke up above the chassis, right? As though they should make solid contact with the brass rails in the chassis cover? And the same for the motor tabs, they poke up above the top of the chassis?

 

With the cover on, can you probe at the rails, i.e., are they visible through the top of the chassis cover when installed? If so, use a voltmeter to see if there's a voltage across the two rails when on the track and the throttle set somewhere that's not off (or one of those buzzing circuit testers, if you don't have a voltmeter). If you get a non-zero voltage reading or a buzz, then it's between the rails and the motor tabs; if you get a zero voltage reading, it's between the trucks and the brass rails.

[scott]

So, it sounds like the problem is somewhere between the springs and the brass rails on the underside of the chassis cover? Or do you think the problem is between the brass rails and the motor tabs?

 

I didn't check the brass rails with the tester, but it definitely looked like the motor tabs would be contacting them. I did check the silver-colored circuit paths (term?) between the springs and the brass rails (at one end of the cover, anyway), and was definitely getting current there.

 

The odd thing was that the circuit paths at each end of the cover seemed to both lead toward a single brass rail. I think I need to review basic electric circuit design to see if I understand this.

 

 

At any rate, this seems a clear case of electrical contact failure (I feel pretty confident in calling this one ;) ).

 

Yeah, I think you can bet on this one.  :)

 

Some considerations, coming from someone who doesn't own a Tomix EMU (so take them with a grain of salt). The springs in the trucks, when installed in the chassis, poke up above the chassis, right? As though they should make solid contact with the brass rails in the chassis cover? And the same for the motor tabs, they poke up above the top of the chassis?

 

I think the truck springs poke up far enough to contact the paths on the chassis cover. There are also four other springs in the frame/chassis, between the trucks and the central motor area, whose function I don't understand. They don't seem to be as consistent in how far they poke up.

 

With the cover on, can you probe at the rails, i.e., are they visible through the top of the chassis cover when installed? If so, use a voltmeter to see if there's a voltage across the two rails when on the track and the throttle set somewhere that's not off (or one of those buzzing circuit testers, if you don't have a voltmeter). If you get a non-zero voltage reading or a buzz, then it's between the rails and the motor tabs; if you get a zero voltage reading, it's between the trucks and the brass rails.

 

I don't think I can reach the brass rails in the middle with the cover on (I'll check tonight). However, there are two circular holes in the cover that give access to the silvery paths while the cover is installed. I'm not getting any power there if I put each end of the tester through one of those holes. But I'll see if there's some way I can do the test you recommended.

[CaptOblivious]

I didn't check the brass rails with the tester, but it definitely looked like the motor tabs would be contacting them. I did check the silver-colored circuit paths (term?) between the springs and the brass rails (at one end of the cover, anyway), and was definitely getting current there.

 

The odd thing was that the circuit paths at each end of the cover seemed to both lead toward a single brass rail. I think I need to review basic electric circuit design to see if I understand this.

 

…

 

I don't think I can reach the brass rails in the middle with the cover on (I'll check tonight). However, there are two circular holes in the cover that give access to the silvery paths while the cover is installed. I'm not getting any power there if I put each end of the tester through one of those holes. But I'll see if there's some way I can do the test you recommended.

 

That's telling. Those holes are for the interior lighting kit; you should be able to detect a voltage across the contacts at the bottom of that hole.

 

Could you post photos of the inside? I'm curious about these silver traces that connect the trucks to the brass rails. My guess is that something has gone wrong here, given the quotes above. I'm also curious about those four other springs…

[scott]

Thanks--I'll try to post some photos of the various pieces and parts once our home internet connection is fixed (today, with any luck, but....).

 

Right now the 115 is in pieces on the dining table...  :P

[scott]

OK, here are a couple of pictures of the innards of the 115, now that our home connection is back up (huzzah!). They're pretty much the  same, but one shows the top side of the chassis cover, and the other the bottom. You can see the circuit paths (silver, not brass, over most, and fairly complex), the truck springs, the four "other" springs (one of which is squished and doesn't stick up as far), the motor, etc.). Still no sign of power getting to the  motor. There was one microsecond where I pressed down on the chassis cover and it buzzed forward a few millimeters, but that's it. I couldn't get it to happen again; maybe it was a short.

 

 

[CaptOblivious]

Oh noes, a Tomix spring-drive! I hate those!

 

 

Damn, but that thing is convoluted.

 

Ok, I've got it figured out. That spring you said wasn't sticking up so high? Is absolutely crucial.

 

I'll draw up a diagram when I get to work that demonstrates the flow of juice through the thing, but in short, power comes in via bottom wheels in trucks, passes through motor, passes through the frame then back out the top wheel. The frame is being used like a second layer in a dual-layer PCB, to route power under the circuit board, so that the interior lighting is in series with the motor (instead of in parallel, like most Kato cars, that just have two rails, no circuit board). Unsure why they chose that route, except that it minimizes current draw.

[CaptOblivious]

OK, I've been thinking about this…for this thing to be not working, there have to be at least two springs on one side not making contact.

 

Also, to install an interior light, you would have to remove all four springs. (Again, a diagram is coming!).

 

Let's suppose the problem is the springs. Run a wire between the two contacts on top of the cover, the round holes where the interior light unit goes. If those springs are the problem, then the motor will run!