# Completely baffled with this issue !!



## GMORR (4 mo ago)

Need help or suggestions please !!
I have an older Athearn Genesis F unit. It is duel mode, DC/DCC. It has only been run in DC.
We just converted to DCC with an NCE basic system. Everything works great. Other locos run like a champ. I put the F unit on the program track for the first time. Turned on the power and the loco took off doing 40mph. I have absolutely no control over anything. All it wants to do is go at a high speed. Tried it on the main with no other engines on it and it does the same thing. I Googled the issue and found alot of people had the same problem. They said it happened with their duel mode decoders only. They said the loco is detecting the track power before detecting any DCC and then it thinks it's in DC and just takes off. They said they went into CV29 and turned analog off so the decoder is DCC only and they never had the problem again. That would be great except how do you change it to analog when the engine is going around the layout like crazy and I can't get any control over it whatsoever.
Tried on both program track and main. Nothing. No matter what I do, I can't get control to where the idling shuts down when I go to program. It's like it is stuck in DC mode or something. Any ideas ? This ever happen to you ? Any help would be great. This is driving me crazy, plus it's my favorite loco and I can't even use it.


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## Severn (May 13, 2016)

Well they do make these rollers you can set the engine on but before you go buying that I'd just try turn it upside down and connect wires to the pick ups in some manner. You know instead of the programming track. Go from there.

Another option is to take the shell off, put the engine in the fuel tank (assuming it's a diesel) so the wheels are raised up. And connect to power input pins of the dcc decoder.

Perhaps there some other approaches...


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## SF Gal (11 mo ago)

Older engines may have a switch on the chip that delineates between DCC and DC. 
I have read some older engines with a digitrax socket that came with a jumper plugged in for DC use.
The jumper may have been removed prior to your purchase. It also could be the decoder chip is defective and will now only run in DC mode. I suspect your going to have to open it up and see what kind of DCC decoder you have. Make sure the decoder doesn't look burn't and troubleshoot from there. Besides if it's a older unit, you might want to clean and lube the gelled grease anyway.


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## GMORR (4 mo ago)

Severn said:


> Well they do make these rollers you can set the engine on but before you go buying that I'd just try turn it upside down and connect wires to the pick ups in some manner. You know instead of the programming track. Go from there.
> 
> Another option is to take the shell off, put the engine in the fuel tank (assuming it's a diesel) so the wheels are raised up. And connect to power input pins of the dcc decoder.
> 
> Perhaps there some other approaches...


Even if I did put it on the rollers, I still can't do anything.The engine just runs and runs. It won't go into program mode. All it does is run and run no matter what I press. Can't program or change anything while the motor is running.


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## Cycleops (Dec 6, 2014)

Whenever I get that it means the decoder is kaput. Not saying that’s what’s happened to yours but there’s a good chance.


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## wvgca (Jan 21, 2013)

sounds like the loco i in DC only ... you sure the decoder is plugged WITHOUT the DC shorting plug in there ?


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## GMORR (4 mo ago)

wvgca said:


> sounds like the loco i in DC only ... you sure the decoder is plugged WITHOUT the DC shorting plug in there ?


I'm new to DCC. Not sure what you mean by DC shorting plug. I bought this new and it only has less than an hour total running time on it. I've never taken the shell off till now, so I haven't changed anything. It's like the day I bought it from the factory.


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## ncrc5315 (Jan 25, 2014)

If I'm understanding you correctly, even when you put it on the programming track it takes off. If your programming track is properly wired, the loco would not be able to move. Are you sure you're wired to the programming terminals, and not track power?


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## J.Albert1949 (Feb 3, 2018)

JMRI makes this easy:








Re the runaway engine:
Do this:
Take ALL your engines off the rails. EVERY ONE.
Now, put the problem unit ON the rails, within easy reach.
Next, with your hand on the problem unit, start up dcc.

IF the engine tries to run away, lift ONE SIDE of it off the rails.
Now, set it back down.
You may have to repeat this a couple of times.

Does it settle down?

If it DOES, then you need to disable DC power conversion.
Again, nothing does this as easily (without disturbing other settings) than JMRI.

If it DOES NOT, and the engine still wants to run away ALL the time, then I suggest you re-check the wiring between the dcc board and the motor.

As mentioned above, sounds like the motor terminals have gotten mis-wired directly "to the rails" (i.e., power pickups), and are NOT going through the dcc board itself.

If NONE of this works, I'd try another dcc decoder...


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## mesenteria (Oct 29, 2015)

If it is a dual-mode decoder, go into OPs Mode (or programming on the main) and select CV29. Then assign it a value of '34'. That removes the ability for the decoder to detect DC, which it thinks you are providing, except now at a whopping 14 volts right off the bat. No wonder it takes off like a jackrabbit. The cure is CV29-34.


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## DonR (Oct 18, 2012)

I don't know that loco or decoder. However, I'm
suspicious of the RED and the BLACK loose wires.
Could they be a bypass of the decoder and are
connected to the motor. 

Normally on a loco with a DCC board you could
have the red and black wires from the trucks. There
may (or may not) be wires to the lights.

Don


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## GMORR (4 mo ago)

ncrc5315 said:


> If I'm understanding you correctly, even when you put it on the programming track it takes off. If your programming track is properly wired, the loco would not be able to move. Are you sure you're wired to the programming terminals, and not track power?


Yes, it's wired correctly. I have an NCE Auto SW switch wired in my system. All other locos work like they're supposed to on the program track. I have changed addresses, changed cv's etc. When this particular loco is on the program track, it just takes off, so I can't do anything with it. It's like it thinks it's in DC mode and doesn't detect DCC signals. I talked to Athearn and MRC, who did the subcontract work for them at the time, and their conclusion was the decoder is faulty now. MRC no longer makes the decoder that was put in those F7's. So, my only choice is to replace the decoder with something else. That's my problem now, I don't know what sound decoder I can put in there to get it running again. I'm not replacing bulbs or speaker, just swapping out the decoder. If you or anybody out there could let me know what decoder I could swap the factory decoder with, that would be great. I have no clue. I assume it would an easy project. I'm new to DCC and need all the help I can get. I have never installed a decoder yet.
Thanks.


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## MichaelE (Mar 7, 2018)

Where is the decoder located on that MB in the photo?


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## wvgca (Jan 21, 2013)

the connections to the front light have been butchered up a bit ... and it looks like the red one has one end connected on the far left hand side of the pcb, and nothing on the right hand end ... the one black wire where it goes to the headlight is also squashed pretty badly
can you still send the loco back and get one that's correct ??...


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## GMORR (4 mo ago)

DonR said:


> I don't know that loco or decoder. However, I'm
> suspicious of the RED and the BLACK loose wires.
> Could they be a bypass of the decoder and are
> connected to the motor.
> ...


The decoder as you see it in the photo is how I got it when I bought it new. I haven't changed anything. I just wish I knew more about decoder wiring to check if maybe its wired wrong. It ran in DC for a long time no problems. I just recently installed a basic NCE DCC system. All other locos run great. I'll have to take the shell off again and really give every wire a look to make sure one didn't come off. I don't have the knowledge yet to tell if a motor wire or truck wire is going to the right place on the board, because I don't know where they are supposed to go.


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## SF Gal (11 mo ago)

Here is some good reading material (ie: pg 2) to get you comfortable with buying and changing out your decoder.... https://www.modelrectifier.com/v/vspfiles/resources/dcc/0001821 diesel Athearn F's.pdf


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## GMORR (4 mo ago)

J.Albert1949 said:


> JMRI makes this easy:
> View attachment 590087
> 
> Re the runaway engine:
> ...


Ok. I checked the wiring and as far as I can tell, every wire is going where it's supposed to on the decoder. The red and black motor wires go to the decoder. I tried what you suggested and when I lifted one set of wheels off and then put it down, it still wanted to go. I looked at my NCE controller and it was saying short circuit detected or something like that. I'm about to give up and just put a new decoder in there, the only thing is, I have no idea which one I can use.
Another thing I noticed when I took the shell off, (this is a Santa Fe F3) is there are two headlights and only the lower headlight is connected. The upper looks like it has a tiny red bulb and a tiny white bulb in it. Those 4 wires are not hooked up to anything. And I don't see anywhere they can be hooked up to. Not sure why they are in there if they're not wired, and what does that upper headlight do if it was hooked up ? I'm getting more baffled by the minute.


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## CTValleyRR (Jul 26, 2014)

Am I correct in assuming that this is a loco you have had for a while, and you just discovered that it doesn't work in DCC? Because it sounds like you have a bad decoder (maybe from day one) and should send it back for a warranty repair / replacement.

If that's not an option, most decoder manufacturers will recommend a decoder for particular locomotives. Visit the website of your preferred source and see.


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## J.Albert1949 (Feb 3, 2018)

Well, if you gave that engine to me, this is what I'd do:

- Decide to replace the existing decoder with a "motor-only" (non-sound) decoder.

- Start searching for a replacement that will fit within the provided space by checking each decoder manufacturer (Digitrax, NCE, TCS, Soundtrax).

- Pull out the existing decoder and speaker, clean up interior wiring if needed.

- Install replacement and test.

It's possible that one of the above manufacturers makes a "drop in" replacement for Athearn Genesis units. Perhaps one with sound capabilities, so you can keep that. You'll have to do the researchin' ...


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## GMORR (4 mo ago)

CTValleyRR said:


> Am I correct in assuming that this is a loco you have had for a while, and you just discovered that it doesn't work in DCC? Because it sounds like you have a bad decoder (maybe from day one) and should send it back for a warranty repair / replacement.
> 
> If that's not an option, most decoder manufacturers will recommend a decoder for particular locomotives. Visit the website of your preferred source and see.


Correct. I've had the loco since around 05-07.
Bought it new. Only ran in DCC till recently, when I installed a basic NCE DCC system. All other DCC engines run fine. I'm to the point where I just want to put in a new sound decoder and be done with it. I've been searching the web and decoders are very confusing when it comes to which one will actually fit and do what I want it to do. I guess I'll just start contacting decoder manufacturers and see if they have something that will work. If anybody is gonna know, it's gonna be the people that make decoders.


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## wvgca (Jan 21, 2013)

GMORR said:


> Correct. I've had the loco since around 05-07.
> Bought it new. Only ran in DCC till recently, when I installed a basic NCE DCC system.


huh ?? i -think- you meant to say you ran it in DC only for most of the time ..


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## GMORR (4 mo ago)

wvgca said:


> huh ?? i -think- you meant to say you ran it in DC only for most of the time ..


Yes, typo error


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## CTValleyRR (Jul 26, 2014)

GMORR said:


> Correct. I've had the loco since around 05-07.
> Bought it new. Only ran in DCC till recently, when I installed a basic NCE DCC system. All other DCC engines run fine. I'm to the point where I just want to put in a new sound decoder and be done with it. I've been searching the web and decoders are very confusing when it comes to which one will actually fit and do what I want it to do. I guess I'll just start contacting decoder manufacturers and see if they have something that will work. If anybody is gonna know, it's gonna be the people that make decoders.


That's what I said in my first post. Most decoder manufacturers have recommendations for each brand and model of locomotive.


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## Cycleops (Dec 6, 2014)

I should just pull out the existing decoder to start again with a clean slate. You have plenty of space there so just about any sound decoder will fit. You can retain the speaker.


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## OilValleyRy (Oct 3, 2021)

I’d look at the Soundtraxx website. Tsunami2 is top of the line, and arguably the best you’ll get for diesels. Typically around $100 but that has probably gone up lately with everything else. 
A budget version, Econami is about half the price, with fewer features.

The website has sound samples of all the prime movers, horns, etc. F units often had Wabco E2 horns fyi, which sound really mean & throaty.


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