Atlas GP38 with Intermittent DCC Troubles

[Dwight in Toronto]

Thanks Peter.  I did put a drop of Labelle at each motor bearing before popping it into the Atlas chassis.

When I put the Atlas flywheels onto the Kato motor shaft, one pressed on nicely.  The other was a no-go.  With my “nothing to lose” approach to this little project, I very slightly enlarged the hole in the brass flywheel, lightly roughened the motor shaft, and joined them with a drop of CA.

That glued flywheel has an almost negligible wobble, but its probably enough to be the source of the running noise.  The noise is more pronounced when running on the test oval, and is much quieter on the bench.

In hindsight, I probably should have tried heating up the flywheel and then pressing it onto the shaft.  Live & learn.

I just got off the phone with Atlas customer service manager moments ago … ordered a new motor assembly.

[Dwight in Toronto]

Just to wrap up this topic - the replacement Atlas motor arrived today.  The new unit readily popped into place, the orange and grey decoder leads were direct soldered to the motor tabs, and the loco has resumed full dcc/sound operation.

Fingers crossed that I don’t ever again have to revisit this thread with another plea for further troubleshooting help!

[jwaldo]

I had a Kato motor that behaved the exact same way as your bad Atlas motor. It turned out one of the tiny wires connecting the windings to the commutator had broken, leaving one of the five poles dead. Not much you can do to repair that unless you are good at very, VERY tiny soldering jobs.

[Curtis Kyger]

@Dwight in Toronto;  Thank you for working through this issue and posting the process.  I too  have had similar issues which I have not yet addressed; so you've provided incentive and insightfulness. Thank you.

[Dwight in Toronto]

jwaldo and Curtis - YES!  A few others with similar experiences!   Not that I would ever wish these sorts of troubles on anybody, but suffice to say that there’s some consolation in knowing that it’s not just me. 

And I can concur that, within the last year or so, I had remarkably similar issues with a Kato ES44AC as well.  In that instance I went through comparably extensive troubleshooting (documented here on TRW), with substantial input from Peteski, but eventually just replaced both the motor and the ESU 58741 sound decoder.  After all that its gone through, I conservatively estimate that that particular locomotive has a sunk cost of about $800!

Thanks for commenting.

[peteski]

Hopefully that fix will be lasting fix (since you replaced both components that seemed to be troublesome).

[Dwight in Toronto]

Yes, fingers crossed that the intermittent “dead on the track” events, for BOTH the Kato and Atlas locos, are behind me.  I’ve spent enough money trying to keep these things operable.