Econami issue with coreless motor?

[delamaize]

Hey everyone, I am working on a N scale Bachmann 2-6-0, which has a coreless motor, and has a Econami installed. It was brought to me for diagnosis and repairs. The owner said that the sound comes on, and everything works, Until you give it throttle, Then it acts like it has an internal short. It cuts power, on the decoder it's self, and shuts down. After a bit, it will come back to life on it's own. It is not causing the breaker on the Base station. (Digitrax zephyr)

I disconnected the motor, and increased throttle. The chuff sounds increase as they should, and it seems to act fine. When I disconnect the motor completely, and apply DC directly to the motor, It works fine, with no binds, or any issues.

I'm not sure where to go from here with this one. the wiring was a rats nest, so I rewired it, and checked for shorts while I was at it, and didn't find any issues. I'm not sure where to go from here, anyone got any ideas?

[NDave]

The Bachman Soundvalue 2-8-0, which has a coreless motor,  comes from the factory with a (proprietary) Economi decoder board. Ran mine for nearly a year w/o issue. When I swapped the tender and decoder on my 2-8-0 (for a Tsunami 2 in a Vandy tender), the 2-8-0s factory decoder/tender ended up with a Bachmann 4-6-0, which also has a coreless motor. It's been running great for 3-4 months now... so I don't know that the Economi design (at least the one coming with the 2-8-0) has a particular problem with coreless motors.

Do you have another motor you can wire to the decoder, to test the decoder's motor functions? I'd also check for an internal short in the motor caused and/or clean the commutator... my (limited) experience is that internal shorts from worn brushes/dirty commutator can be intermittent.

Good luck!

[peteski]

Like NDave mentioned, it would be good to test the decoder with another motor.  As you describe it Motor seems to work ok on DC), there might be a problem with the decoder itself, but using another motor (preferably the same motor as is used in that model) would be the best test.

As for checking the commutator, these cheap coreless motors have no way to access the commutator/brushes other than prying out the back motor cover (which also holds the metal-leaf-type brushes).

While not Bachmann motor (it is a similar Kato FEF-3 motor), this photo shows the commutator  and brushes.

[delamaize]

Ok, so I checked the decoder using another locomotive, that didn't have a tender. attached the motor and power leads to the loco. I didn't have any issues. I checked though the original locomotive again, and didn't find any shorts or issues. I was going to check the amperage draw for each locomotive, and each type of motor (coreless Vs Standard 3 pole can), but my ammeter broke the other day, and I have not had a chance to get another one.

Checked though a few other things, with no luck. So I decided to go to my old stand by, Factory Reset. That did the trick, it would actually run for very short distances now. Cleaning wheels, contact points, and track is always my first go to. But I decided to re-clean the wheels, and my test track. That improved things a little. So I now have a pick up issue.....

Did some investigating, The tender is the issue now, I'll explain. It's a Model Power short Vandy, that the owner had shortened even more. It's an ok job, not perfect, but passes the 3' test. Well that is the root of the problem now, The tender wasn't square when it was spliced back together, and it's twisted. So the front truck doesn't sit square on the rails, the wheels on the left side, sit about 1/2 mm off the rail head, Add a ton of weight, to force everything strait, and it improves drastically. Not to mention it still uses the old MP pick up, where one truck picks up one rail, and vice versa.

Now I gotta get with the owner and see what he wants to do next. If he wants me to go to town on it, cut the tender up, and try to square it up. And I need to find a way to get pick ups from both rails on it. I wish I knew what CVs changed with the reset to cause the improvement

Until I get an answer from him, It's on to the other project I have from the same client, a ConCor 2-10-2, with a old Bachman vandy tender, that has an intermittent short, that is totally random.

F U N

[peteski]

Glad that you got things figured out, and I'm surprised that NDave and I didn't suggest factory reset - that is usually the first step in troubleshooting oddball problems. Shame on me.