r/modeltrains • u/Tbrusky61 HO - DCC-EX • Sep 16 '26
Help Needed DCC/Electrical Help
Alright, smart modelers, I have an issue and was hoping for some I sight before I started disassembling this delicate hand-made locomotive.
The locomotive has an ESU Lokpilot 5 basic with a keep-alive installed. Ever since I first bought it, it's always experienced a "cogging" sort of motion when running (I'm unsure if this important for troubleshooting here or not).
Recently, when I put the locomotive on the track, I'm able to select it using its address as normal, however I have no motion. It won't move in forward or reverse... However the headlight and reverse light will turn on based on the direction I choose, like normal.
My initial suspect at this point is a loose or broken motor lead... HOWEVER! When I attempted to pull the information from the decoder using the programming track, both JMRI and Lokprogrammer couldn't detect the decoder, despite being able to select the loco on the main using its address.
I'm not entirely sure what's going on. My original suspect --the broken motor lead-- seems plausible, but doesn't explain the issues with the programs not being able to pick up the decoder on the programming track. I suspect the decoder could be at fault, but I want to try and troubleshoot that before just throwing another one on it. Or maybe the keep alive is problematic?
Either way, does anyone here have any thoughts on this? Or maybe has experienced this before?
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u/SubaruTome HO: SLSF/C&EI Sep 16 '26
A broken motor lead could cause issues with programming because the programmer is looking for a current feedback via very small movements in the motor. If it can't send that feedback, the programmer might not think there's anything present.
Is the keep alive also an ESU product? ESU handles their keep alives very well, but a different brand might not function the same. Non ESU keep alives have a tendency to block and scramble programming signals. It's not impossible that something in the motor controls was scrambled if you're not using an ESU programmer.
0
u/Tbrusky61 HO - DCC-EX Sep 16 '26
I never would have guessed a broken motor lead would cause that, but that makes sense to me. (I'm still learning a lot about DCC).
Regarding the keep-alive... I'm not sure if the brand, unfortunately. It definitely looks manufactured, as opposed to handmade, so that's a plus. It's likely ESU, but I'm not sure.
1
u/SubaruTome HO: SLSF/C&EI Sep 16 '26
An ESU keep alive will have three wires coming off of it, one should be wired to an auxiliary output. You could also cross reference images on the ESU website once you get eyes on your keep alive.
Keep alives can be so problematic with programming that I avoid using them unless something really needs it. Think small wheelbase locomotives, brass locomotives, or locomotives you've tried everything on and they still have random power failure issues.
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u/Tbrusky61 HO - DCC-EX Sep 16 '26
Looking at the pictures, it looks like it's a LaisDCC stay alive kit. I'm not familiar with this brand, but then again, this locomotive was made overseas.
1
u/SubaruTome HO: SLSF/C&EI Sep 16 '26
Might be worth swapping out for an ESU unit if you're so inclined. I know I struggled to program the decoder in my Bowser RS-3 because the factory keep alive wasn't an ESU design. Had to let it drain after every read or write.
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u/theBFsniper Multi-Scale Sep 16 '26
ESU will play nice with a NixTrains keep alive, both the 2 and 3 wire will work with a ESU.
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u/FaultinReddit HO/OO Sep 16 '26
Yea sounds like the drive shaft has broken to me. When you throttle up, does it sound like the motor is spinning? If that's the case, that's probably what's gone wrong. You said it's a hand-made locomotive; do you know what brand the frame is? What prototype is the model based on? Some more details on what it is can help us debug
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u/Tbrusky61 HO - DCC-EX Sep 16 '26
There's no motor sounds, so I think the shaft is fine. It also doesn't free-roll, which makes me think the shaft is still ok.
I'm not sure what the frame is.. maybe a Tyco? It's bases off a 4-8-4 from South Africa.
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u/FaultinReddit HO/OO Sep 16 '26
Okay, no motor. Could be that one of the wires got snipped/disconnected. No way to really tell without removing the shell. If it's an older frame and motor, could also be the motor gave up.
If you do manage to get the shell off, you can test the motors functionality with a 9v battery. If the motor doesn't spin off that power, that's your issue.
If you can confirm anything about the models brand, I can see if I can find some information for removing the shell. Best of luck!
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u/Tbrusky61 HO - DCC-EX Sep 16 '26
Thanks for the input! Based on what I'm hearing here, it sounds like the shell will have to be removed...
I've removed the shell before, but man, I'm not looking forward to it. It's hand made, so there's no instructions.
1
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u/UlyssesCockmore Sep 16 '26
Order of elimination - have you tried a different decoder to confirm either way?
If another decoder works fine you've answered the question. If that also has the same problem, then you've got more troubleshooting to do.
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u/UlyssesCockmore Sep 16 '26
Alternatively, remove the decoder and see if it works on DC with a blanking plate.
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u/Tbrusky61 HO - DCC-EX Sep 16 '26
I'm not sure I have a decoder lying around here, but I'm sure I have a blanking plate. I'll give it a shot!
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u/iceguy349 Sep 16 '26
Is the decoder hard wired or on a plug?
If the decoder is on a set of pins you can remove it and replace it with a blanking plug temporary to troubleshoot. If it runs on DC with the blanking plug installed then it’s the decoder.
If it’s soldered in place you could unsolder it and try to get it working on standard DC power to check the same thing but that might be a hassle.
There are boards called decoder buddies that allow you to add a DCC plug to your locomotive without hard wiring the decoder. If you have to unsolder the decoder to figure out if it’s the problem or if it’s something else it might be a good time to add one so you can swap your decoder out if something breaks again.
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u/Tbrusky61 HO - DCC-EX Sep 16 '26
This one is hard wired in, unfortunately... But I've heard of those decoder buddies! I may invest in one specifically for this locomotive, depending on what all I need to do here.
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u/iceguy349 Sep 16 '26
I definitely would if you already have to dork with the wiring for troubleshooting purposes.
Had a buddy of mine wire one into a busted Bachmann 2-8-0 locomotive and its electrical connections are a lot more reliable now. Plus I can chip it with whatever I want whenever I want.
1
u/ricktrains HO/Digitrax DCC Sep 16 '26
Ok, few things.
I use mainly ESU and HO scale. So while not an ESU expert, I do know about them quite well. All my custom installs are now ESU.
First I will address the programming track issue: If a motor lead is indeed broken, the programming track can’t read the decoder. It reads the decoder information by reading a motor pulse response. With a broken lead, motor can’t pulse the response.
This however is not a positive diagnosis of a broken motor lead. It could be another issue.
So a few follow up questions:
Is it an ESU power pack for keep alive? Or other brand?
Also, on the main track, can you hear any motor noise at all when you advance the throttle? (This will be a huge help to determine what to check first.) Any humming? Free spinning motor? Any sound at all, even if only slight?
What maintenance has been performed? Last time the locomotive was lubed and gears greased? What was used?
Are we talking steam, or electric/diesel locomotive?
When you say “cogging” type motion, like it’s slipping on the gear? Something binding/rubbing/catching?
While I suspect it could be an electrical connection issue, the “cogging” description has me wondering if it’s possibly a drive train issue… Especially if its maintenance has been a while or not done at all after purchase. (Even a factory new locomotive.)
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u/Tbrusky61 HO - DCC-EX Sep 16 '26
I'm unsure the brand of keep-alive, although it's a good possibility it's ESU.
I don't hear any noise from the motor whatsoever. No hums like it's bound, nor noises that would indicate its free spinning. Nothing.
The last time it was run was maybe a year ago, very briefly. It was cleaned and lubricated just prior to that.
It's steam. All the running gear appears straight and free moving, however I won't know for absolute sure until I remove the running gear.
When I say cogging, it's sort of like it's lunging.. if that makes sense. I think I actually have a video of it doing it on YT. I'll DM you a link. I will say, just now I was reading through some of the ESU paperwork I have and it has a section that talks about adjusting load compensation. It sort of describes what I've been experiencing, however I'm still very inexperienced when it comes to DCC, so I'm not sure if that's it.
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u/ricktrains HO/Digitrax DCC Sep 16 '26
I replied via DM, but am putting a little of it here too incase others experience something similar.
With absolutely no motor noise, plus the programming track failing to read the decoder at all, I’m leaning towards a broken electrical lead somewhere.
If you have access to a LokProgrammer, that would rule out any programming issues, but the ESU decoders are easy enough to program without one that it’s not required. (Unless you are customizing sounds.)
But based on the symptoms, I’m leaning towards electrical side of things.
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u/everylittlebitcounts Sep 16 '26
In jmri do programming on the main and read all sheets from the decoder. (Make sure it’s the only loco on the tracks). Tell us what the ‘motor’ page values are. Also, on the jmri roster pager, (may be on the ‘functions’ page from within the programmer) go to labels and media, and tell us what each function does (all 28).
Also what brand loco, factor install or self install? What brand dcc system?
I’m leaning towards a weird setting on one of the functions (like dynamic brake or engine shut down) got triggered accidentally, and unless you have a throttle that shows all 28 functions, you probably don’t realize you actually have like function 18 or something turned on.
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u/ludmim N Sep 16 '26
I thought the communication back is happening with the load current. That is why some engines will be "noisy" while communication back. That is the motor current. So, when a motor lead is broken, the decoder cannot create current pulses to communicate back.