I would say it is likely to be mechanical, most likely wear on the gears that affect the driving side of the gear face. When turning the wheels with your fingers the gears are using the opposite face of the gear teeth, and that side may not have the same amount of wear on the teeth. So I suspect you will need to inspect the teeth on every gear to check the shape of the teeth.

The other thing to check is the wear on the pins that gears are mounted on, or the corresponding bearing hole in the gear. When the wear gets bad the gear can move far enough that it will jam between the two mating gears.

I remember when my father was repairing locos, when I was still at primary school, he replaced gears that instead of the teeth looking nicely rounded looked like pieces of hair sticking up when attracted to static electricity. I suspect the quality of brass available back in the 50s wasn't that good and the wear rate was quite high.

Ah!

Great ideas.

I’m actually going to try ESU permanentg magnet with the original armature. As I recall no such problem was when this was still Delta.

The orignal parts are in pristine condition too. Should get the magnet in a few days.

Yeah… I’ll inspect the teeth. Good point!

Got to get this loco working. I’ve put so much work on it as it has:

- Telex both ends
- Rear lights red/yellow depending on direction
- Flickering firebox
- Keep alive
- Switching maneuver programming
- Smoke unit

-Eino

Hi,


Getting back to this. I’m still not 100 % sure where the problem is nor how to fix it.

I watched YouTube for ESU magnet + three pole armature conversions and they run much better. So the conclusion is that there must still be a mechanical issue.

What do you think, is there anything I can do?

The teeth in the gears look fine to me…

-Eino

Hi. Rods are fine. Without an armature in place they move freely. No friction.

Also none of the bolts are pushing out and hitting/locking the adjacent rod.

I Was kind of hoping to find the issue in the rods, but the work perfect.

-Eino

btw in your first youtube the side rod looks bend outward near the last coupled axle on the visible side. they should be straight to not create friction in the turn

Hello Eino,
Have you tried unsoldering one of the leads from the motor shield and running the loco on a plain DC controller. This will show if the problem is decoder/settings related or a physical problem with the motor, gears or rods.

Paul

HI Eino,

Yes, I think that controller will be fine for the test. I usually use a bench power supply for testing these sort of motors when doing servicing and 6-8 volts is enough. You only want to spin it relatively slowly after all.
I would unsolder one of the wires from the decoder first as it probably won't do it any good to have a voltage applied to its outputs.

Good luck
Paul

Hi guys,

So I finally got the time to drive the motor (3-pole+hamo magnet) with direct DC.

Guess what? No issues!

So it has either got to be the decoder or the project I’m using.

The base for the sound project is the latest V60 as I wanted to have a project with switching maneuver + telex ready made. Doing that setup from blank project is too difficult for me.

I’ve ofcourse changed the motor type and run calibrations too.

Everything else does work great with the decoder AND initially with 5-pole motor, worked too. So I’m pretty convinced that the 5-pole armature does not quite fit as suggested above and caused a jamming of some sort... If it has not been rotating properly could it have damaged the decoder?

Another theory is that the project is not good…

Which of the Märklin projects is the default steam loco project that comes preloaded? I’d like to try that…

Here is a video:



Thank you!

-Eino

Hi… ah yes.

So I’ve now fitted the loco with another 5-pole anchor. This one is green colour as the previous (and broken one) was black. I don’t know if the gear is any different.

Also the decoder is loaded with the factory msd3 steam project that I found on Märklin mSD3 product page’s downloads.

I’ve also calibrated the motor BUT it may be that it worked better without calibration. Mid speed is kind of jerky/sticky but slow and very slow speeds are just beautiful. High speed is ok…

All that is still a bit strange but see this video and you’ll get the idea:



Not sure if there is really anything that can be done. I really don’t understand the motor control CVs so can’t really fine tune anything manually.

-Eino

…no the shell’s got nothing to do with it…

-Eino

Glad you got it resolved and you are happy although the solution applied seems odd to me.

If the loco shell puts pressure on the motorshield, causing the axle to be crooked, I would think you would want to modify the shell or motorshield externally to avoid both touching, but not modify the axle hole itself. If without shell the axle is straight enough to work fine, it should also be like that with shell. Now with your enlarged axle hole you risk having too much play on the axle resulting in excessive wear/noise. How sure are you it will not get stuck again when the brushes wear a bit or something?

Have you checked the shell on the inside for marks where it touched the motorshield? Is not just some material in the way like a burr of something that can be dremeled out?

BR,
Bert

Hi guys,

good points.

The retrofit set is the correct one for sure.

The enlarge axle hole in the motor shield is perhaps 0,05 mm more. Not over a tenth anyways and it had a tremendous effect. I don't believe it will cause so much freeplay that later on problems arise. And if they do, it's most likely from brushes wearing badly. That of course is then an easy fix just to replace the brushes. This is something we'll see in the future.

I rather not dremel the loco shell as it is in perfect shape and don't want to risk any damage to it.

I've previously done all kinds of modifications like fliper motor shield parts upside down for an BR18 Delta etc, and really don't want to do that kind of modifications anymore, so doing a ~5 circular motions with a diamond file was quite an easy one this time. Yes it is a hack but for my some short experience and reading other peoples experiences, these kind of hacks are sometimes required.

-Eino