ANSWERED: LGB 21750 - a few repair questions

[idlemarvel]

I hope someone can help me with a couple of questions:
1. What is the purpose of the coils in this picture? They are wired into the motor leads on the 4-wire motor block plug. I am planning to remove them unless someone tells me otherwise. I am confident they are factory fitted; the document for decoder fitting from Massoth (for the 20750) says "The locomotive also runs faultlessly with coils (with Massoth decoder) but has a reduced engine power under load. By bridging the coils, however, they lose CE approval for the vehicle!". So I guess they are to do with some kind of European conformance test, but I've never seen them on any other loco.



2. The lighting LEDs have blown, so I'm looking for replacement for these. There is no mention or reference to these in the documentation. The black thing is a piece of plastic to held the LED with two holes for the legs of the LED to pass through, so I guess any LED will do as a replacement?



Thanks, Dave

 

[PhilP]

The inductors will be for suppression..
You should not need them, but if Massoth say they can stay, why remove them?

PhilP

 

[Greg Elmassian]

Coils can "trap" interference caused by the motor. Why do you want to remove them? The interference they "trap" is beneficial. If you are not experiencing any issues I would leave them. You could possibly cause interference in your radio system and perhaps even the decoder. Why take a chance?

Well, any flat topped led would be a replacement, they may have a more diffuse light pattern than a round top. Electrically yes, all the same (for the same color).

Greg

 

[idlemarvel]

Thanks PhilP and Greg Elmassian I'll leave the coils in place, and thanks for the advice on the LED. Case closed.

 

[Greg Elmassian]

In the old days, these coils often interfered with decoder motor drive, to wit: dampening the BEMF signal. Modern decoders seem to tolerate these inductors better.

If you did have some issue with BEMF not working right, temporarily shorting each would be a simple debugging step.

Motors make a lot of electrical "hash" and keeping it out of the decoder wiring is a good basic practice for the decoder and other home electronics.

Greg

 

[idlemarvel]

I've taken dozens of LGB and PIKO locos apart, I wonder why I've never seen something like this before?

Thanks for the tip on BEMF.

 

[Greg Elmassian]

bachmann has been doing it for some time, perhaps CE is getting tougher? the components i see are usually smaller

 

[PhilP]

Bachmann could possibly do with fitting physically larger items?

I regularly see those in the 'Thomas' range, melted into the model.

PhilP

 

[Greg Elmassian]

Yes, Bachmann often fitted both inductors and capacitors, and of low quality right to the motor brush leads. The capacitors are cheap, but undersized (wire gauge) inductors can easily generate heat as you say.

Most people remove them prior to a problem. The ones pictured are ungainly, but well sized, and not contacting other things should they get warm.

Greg