# Problem between Digitrax and MRC decoded trains



## Raymond (Aug 15, 2015)

Sorry, I'm a little new to this. I've tried searching for an answer, but couldn't find anything about this specific problem. I've run an MRC Command 2000 for quite some time now (probably around 2000.) I currently run several DC trains, a Bachmann Acela running on DCC ID 2, a Walther Alco FA-1 (New York Central 1000) on ID 4 and (I think) another Walther FA-1 (Union Pacific 1500A) on ID 5. There is no other DCC equipment attached to the tracks. All of these work fine on my MRC.
I purchased a Zephyr because I was interested in upgrading my system to use JMRI. When I tried the Zephyr on my track, I found that the two Walthers wouldn't run, but the Bachmann (and the DC trains) would. I thought the system was defective and returned it. I then decided that I would rather have the Digitrax SEB Xtra. Bought that and found I had the same problem. Since my setup is pretty old, I made a separate test track from some EZ-track that came with the Acela. I still have the same problem with the test track. I tried writing a new ID to the Walthers using the Digitrax system. The walkaround says "Write" and the trains bump, but they still can not be controlled by the Digitrax. When I put them on the Command 2000, they also will not run, but reprogramming them on the Command gets them to start working again.
I've tried different IDs, using the track, using a programming track, putting a load across both the track/programming track. I'm out of ideas.


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## Brakeman Jake (Mar 8, 2009)

Do you still want to use the MRC system?It seems you are having communication protocol dfferences between the two systems.I know nothing about the Command 2000 so can't help you there.
I'd try re-programming a loco with the Digitrax set,with CV29=34 and then write a four digit address to see what happens.Then let us know,if the loco runs it will confirm my guessing.


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## wvgca (Jan 21, 2013)

the command 2000 [ i think] writes a little differently, especially when you use the sliders for acceleration and momentum programming, i still have a 2000 unit someplace .. you may have to use the zephyr to try and 'reset' the loco decoder to the 'factory default' settings .. there is no NMRA standard for this, if your zepyhr will read back cv8, the number returned will give you the make id of the loco dcoder ..
ie..lenz id 99 reset cv 8=33, nce id 11 reset cv30=2, digitrax id 129 reset cv8=8, there are other reset values depending on the decoder maker ...i changed over to a mrc quite some time ago, but don't remember if i had any problems at that time..


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## Cycleops (Dec 6, 2014)

It does sound like this is a compatibility issue. You will need to reset the decoders to their factory default settings as wvgca has suggested. Let us know if this sorts things out.


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## Raymond (Aug 15, 2015)

Thanks for the info, I'll try 4 digit addressing and reseting to factory defaults. I don't think I can read in the CV values however. I think that the Super Empire Builder doesn't support reading, just writing.
I don't plan on using the Command 2000 further as long as I can get the Super Empire Builder to run the other two trains.


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## CTValleyRR (Jul 26, 2014)

The command 2000 was MRC's first foray into the world of DCC, and it's part of what gives the company a bad reputation in DCC (the other being the spotty quality of their decoders, which unfortunately they still haven't totally fixed). Not that it was a bad system, intrinsically, just that it wasn't even state of the art when it came out. As WVGCA alludes to, it used a slightly different programming method, and did not allow access to all CV's for programming. IIRC, it also used some unconventional methods to access bell and horn functions using throttle settings, which may be at the root of your problem. It was also only capable of 14 speed steps, and your Digitrax may be choking on that as well.

My recommendation would be to reset the decoders to their factory defaults, then reprogram them using the Digitrax. If that doesn't work, check to make sure you don't have some crappy old MRC decoders in those units. If you do, replace them.


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## Raymond (Aug 15, 2015)

Okay, another question. I'm running with the Empire Builder and I'm using a LocoBuffer to connect to DecoderPro/PanelPro. From what I've read, there's no way to read CV8 or any CV value with that setup. The Command 2000 also doesn't support reads. I've never changed out a DCC module before, but I was wondering if it's a simple process to find the type of DCC by just opening up the trains. In other words, would it have the manufacturer's name on it?


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## Raymond (Aug 15, 2015)

I think I answered my own question somewhat. I dissembled one of the engines and it has what certainly looks like a decoder marked "MRC TER-414W". Darn thing is directly soldered, no plug.


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## Brakeman Jake (Mar 8, 2009)

Even if they are MRC decoders,if you don't have burned spots and/or strange smells,they may be still good.

Since you can't read them,you still may be able to re-program them "blind".Writing CV8=8 should reset them,then try CV29=34 then write a four digit address.These MRC decoders have a tendency to be somewhat resilient to standard DCC programming so a few attempts may be in order.

If they are "sound" decoders,your programming track may lack the necessary punch.You may have to program on the main,using "Ops mode"...see your Digitrax booklet on programming.Remove all other locos from track then.


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## Cycleops (Dec 6, 2014)

Raymond said:


> I think I answered my own question somewhat. I dissembled one of the engines and it has what certainly looks like a decoder marked "MRC TER-414W". Darn thing is directly soldered, no plug.


Are you sure there is no plug? Because some plugs use a pub it may look like there is no plug. Check it again. Post a pic if you can.


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## wvgca (Jan 21, 2013)

if you want to do a factory reset on a mrc decoder, cv8=8 is not valid .. depending on age , real old ones cv8=33, newer ones cv125=1 re the factory reset cv values ..
cv8=8 is valid for Digitrax,Loksound [ESU], TCS and SoundTrax Tsunami decoders


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## CTValleyRR (Jul 26, 2014)

Cycleops said:


> Are you sure there is no plug? Because some plugs use a pub it may look like there is no plug. Check it again. Post a pic if you can.


Back when the Command 2000 came out, it was fairly standard practice to directly solder the darned things in. Plugs came later (after people realized that a less permanent solution was a better option).


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## Raymond (Aug 15, 2015)

Tried the reset CV8=8 and CV29=34 on both trains and neither worked. I'll see about posting a picture but, yeah, I'm really sure about them being soldered. For example, the front light is directly connected to the board.


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## Raymond (Aug 15, 2015)

Sorry also tried CV8=33 and CV125=1. Neither worked.
I suspect I'm just going to have to get two new engines or a PR3 to see if I can recover these two. It's a shame because I've already spent money on the SEB and the Locobuffer.


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## Cycleops (Dec 6, 2014)

Why don't you just fit a new decoder? Is that doable if the currant one is soldered?


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## CTValleyRR (Jul 26, 2014)

If Chantilly is the one in Virginia, US, there are several companies who can replace the decoder for you, if your soldering skills aren't up to the task. It's not that hard to break or remove a soldered joint.

But yes, definitely, changing out the decoder (especially if it's an old MRC one) is better than buying a new loco.


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## Raymond (Aug 15, 2015)

Soldering's not so much the issue as soldering tiny wires. I can see about someone doing a replacement for me. Still more expense, no matter how you look at it.


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## Cycleops (Dec 6, 2014)

Scolding tiny wires isn't so different from soldering big ones, honest. Just tin each one with a small amount of solder, twist together and apply the iron. Remember to put a length of heat shrink, far enough away from the soldering so it won't be affected and then slide into place when cool. Plenty of vids on YouTube to show you the way. Give it a go.


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## DonR (Oct 18, 2012)

Cycleops is right. Twist the decoder wire strands, dip in flux and apply a dab of
solder to each wire end. Use flux and a tiny dab of solder on
each connection point they will go to. Then, you need only
hold the wire to it's connection point and carry a tiny dab of
solder on the tip of your iron to it. A deft touch of the iron
and you have a solid connection. If you are near a sensitive
component protect it with a heat shield of some sort. Often
a damp cotton ball will be sufficient.

The decoders all a standard wire color code and come with
clear instructions as which wire goes where.

It really is a simple chore.

Don


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