Why Does My DC/DCC Locomotive Not Work?


GuilfordRailman

GuilfordRailman

Well-Known Member
I recently purchased a project locomotive online for my next layout build.

It is a DC/DCC locomotive. When tested the DC mode worked great! When I tested it into DCC mode, the locomotive did not respond.

Upon placing it on the track, it immediately made a low humming noise. I read through the NCE instruction booklet on how to program a new address into the locomotive because I didn’t know the current one. According to the power cab display, the decoder is responding (manufacturer 255). However, when I try to move it forward or reverse the humming noise increases slightly but no movement occurs. Any ideas?

I am fairly new to DCC locomotives, and this is my first DC/DCC locomotive.

Any thoughts or suggestions would be really helpful:)
 
Is this a PluX18 or 21MTC Loksound 5 decoder? If so, any approximate year of manufacture?

ESU decoders made in 2021 and about half way through 2022 unknowingly used substandard components in some of these decoders causing the motor circuit to fail. Specifically, the Chinese were using anything they could source for the voltage regulators. These can fail unexpectedly, or slowly die within hours on first installation.

ESU acknowledged these failures and identified the cause, but to date they claim not to be able to reproduce the failures under controlled lab conditions. They will replace these decoders within the two year warranty period if purchased separately from the locomotive, but for a failure from a factory supplied decoder, the locomotive must be returned to the retailer or manufacturer.

I have so far, had two of these replaced and they failed as well.
 
RhB Michael said:
Is this a PluX18 or 21MTC Loksound 5 decoder? If so, any approximate year of manufacture?

ESU decoders made in 2021 and about half way through 2022 unknowingly used substandard components in some of these decoders causing the motor circuit to fail. Specifically, the Chinese were using anything they could source for the voltage regulators. These can fail unexpectedly, or slowly die within hours on first installation.

ESU acknowledged these failures and identified the cause, but to date they claim not to be able to reproduce the failures under controlled lab conditions. They will replace these decoders within the two year warranty period if purchased separately from the locomotive, but for a failure from a factory supplied decoder, the locomotive must be returned to the retailer or manufacturer.

I have so far, had two of these replaced and they failed as well.
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I am not sure what decoder it is. The locomotive didn’t come with instructions. I will probably have to open up the locomotive and see for myself.
 
Based on some research so far, I’ve read that dual mode decoders can have issues. Some members on other forums have indicated you can adjust CV29 to switch from dual mode to DCC only. I wonder if this is worth a shot?
 
It would be worth trying. There is an additional note I will add. If this decoder has a stay-alive capacitor network installed, depending upon the values used, it can sometimes appear to the DCC system as a DC locomotive and it will not respond...even if it is a dual-mode decoder. What is more common is the decoder not responding to programming input because of the stay-alive. They will still usually run fine with this installed.
 
RhB Michael said:
It would be worth trying. There is an additional note I will add. If this decoder has a stay-alive capacitor network installed, depending upon the values used, it can sometimes appear to the DCC system as a DC locomotive and it will not respond...even if it is a dual-mode decoder. What is more common is the decoder not responding to programming input because of the stay-alive. They will still usually run fine with this installed.
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Okay, I will give it a shot! Before I do that, I’m going to remove the shell and see what it looks like. Might take a few photos so others can see what’s inside and be able to provide feedback.
 
Here are a couple photos of the inside. As mentioned previously, I'm relatively new to DCC and so I don’t really know what I’m looking at.

IMG_8289.jpeg


IMG_8288.jpeg


Edit:

This is an Atlas 342 4-function dual-mode decoder.
 
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Well I figured out the issue! The 6 pin plug you see in the photo was positioned in the DC only spot. I moved in over to the next set of holes and the locomotive now responds to DCC control.

However, the lights don’t work. Any ideas on that?

Edit:

Lights are now working but I believe the problem is a loose wire or connection for them. They flicker frequently and the brightness changes at the same rate. Will have to investigate further. Not sure the best approach to repair something so small.
 
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GuilfordRailman said:
Well I figured out the issue! The 6 pin plug you see in the photo was positioned in the DC only spot. I moved in over to the next set of holes and the locomotive now responds to DCC control.

However, the lights don’t work. Any ideas on that?

Edit:

Lights are now working but I believe the problem is a loose wire or connection for them. They flicker frequently and the brightness changes at the same rate. Will have to investigate further. Not sure the best approach to repair something so small.
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Honestly, the best thing is to replace the decoder with a more modern model. That decoder is, to be charitable, a "basic function" model, and you will never be happy, or even satisfied, with it. They were made by Lenz back when DCC was first becoming popular, and they supplied them as a cheap way to offer DCC equipped engines.
It's probably 20+ years old, and will act it.
 
bnsf971 said:
Honestly, the best thing is to replace the decoder with a more modern model. That decoder is, to be charitable, a "basic function" model, and you will never be happy, or even satisfied, with it. They were made by Lenz back when DCC was first becoming popular, and they supplied them as a cheap way to offer DCC equipped engines.
It's probably 20+ years old, and will act it.
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At some point in the future I will upgrade all decoders but for now a basic function decoder is all I need:)
 
I've seen that decoder style used in some of the first Atlas engines to get factory-installed dcc (Non-sound, back then).

I had one in an Atlas SD35 that seemed "buzzy", so I replaced it.

BUT... I have another Atlas GP40 from about the same time (and I'll presume with a similar decoder installed at the factory), and it runs great.

Questions:
Once you figured out the solution for dcc was to move the jumper, how does the engine RUN configured with the current decoder?
Is it smooth?
Is it quiet?
Those are my "main criteria".

RE the flickering headlights:
Are the wheels clean?
Do the headlights "flicker about the same" in both directions?
Or is one worse than another?
If one is worse, could be the connections to the light/decoder board (we can't see them because they're the "inside" connections on either end of the board).
If they flicker the same in both directions, could be dirty track or dirty wheels.

Just about everything I have is non-sound, motor-only dcc. I see occasional headlight flickers, but that's almost always an indication of a stretch of track that needs cleaning or wheels getting dirty.

If you think about replacing that decoder, be aware that a Soundtraxx MC2H104at will drop right in with all the connections in the right places. Relatively cheap, too (it's motor-only, hence the "MC"). I usually buy decoders from yankeedabbler.com.
 
GuilfordRailman said:
At some point in the future I will upgrade all decoders but for now a basic function decoder is all I need:)
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There were two different versions offered. One was more basic than the other. The base model wouldn't do much, other than run the motor and maybe control the lights. The better one offered 4 digit addressing, and you could configure it to either be silent, or have better motor control.
If you try changing top motor speed, you'll find it won't work, and you'll need to load speed tables in either version. Both generally lit headlights (bulbs) without flickering, so you may have a contact problem with pickup or bulb connections.
 
J.Albert said:
Once you figured out the solution for dcc was to move the jumper, how does the engine RUN configured with the current decoder?
Is it smooth?
Is it quiet?
Click to expand...
It runs smoothly and it relatively quiet, just a slight humming noise.

The lights flicker more on one side than the other. Could also be the track! Sometimes the lights cut in and out entirely so my guess is a connection issue.

Good to know about which decoder will fit in there! I’ll keep it in mind for when I upgrade in the future.
 
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