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I have an older Bachmann loco that makes a loud hum when starting. It is EMD GP40 loco. Dcc on board. Will changing decoders help? Road name is SF 3501. Thanks.
 

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Did it come with any information on the decoder itself? My experience with Bachmann-branded decoders is that they are buzzy, especially at low speeds. Based on that, I'd say swapping the decoder for s higher quality one may help.
 

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I no longer doubt it.

I have an older Bachmann loco that makes a loud hum when starting. It is EMD GP40 loco. Dcc on board. Will changing decoders help? Road name is SF 3501. Thanks.
artp51;

In light of the many other responses saying that Bachmann decoders are not very good, and often do make buzzing sounds, I have to withdraw my speculative reply. Apparently it actually is likely that the decoder inside your Bachmann GP-40 is causing the noise.

good luck;

Traction Fan :smilie_daumenpos:
 

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Heya Milliken, you're just up the road from me (Longmont)!

Definitely need more information on exactly what is happening. Does the train actually move when you issue DCC commands, or does it start humming as soon as you put DCC power to the track but never actually moves? If the latter is what you see, then your loco is most likely jumpered for straight DC operation and doesn't actually have a decoder in it.
 

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I have the Santa Fe 2-10-4 and it’s the only loco I have that is Bachman that doesn’t hum other than my doodlebug but that has an nce decoder in it already
 

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The Bachmann "DCC On-Board" GP7 & GP30 I have are hideous growlers... very annoying.
I'm about to modify them both for a private railroad, but they'll need good decoders for their debut.
In addition, I'm also in the market for a GE 70-ton end-cab, (only made by Bachmann) and virtually every one I've tried is a growler.
 

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If the latter is what you see, then your loco is most likely jumpered for straight DC operation and doesn't actually have a decoder in it.
Dang, I've always thought that DCC power to a straight D.C. loco was a death sentence.
 

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I think I just learned something... maybe.
Bachmann DCC locos are equipped with an RF choke, which even Bachmann says emits a 'moderate' hiss or buzz.
I'm now wondering if this trait has somehow advanced into a growl.
 

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Dang, I've always thought that DCC power to a straight D.C. loco was a death sentence.
It is! The board I'm referring to has a plug-in jumper module which directly connects the rails to the motor so that the loco can run on DC track. If you unplug that jumper and plug in a DCC decoder then you can run on DCC track.

And honestly, I think I'm going to get rid of that board this weekend. It takes up half the space inside the tender and the only thing it really does is add a couple diodes so the forward and reverse lights will operate automatically when you're using DC. I just have to remove the wires and reconnect them to my own 8-pin socket and I'll have plenty of space for the decoder and speaker (right now I have the tender shell removed and everything held in place by a rubberband).
 
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