Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Athearn DCC Board Replacement - Never Again?!?

13 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    April 2003
  • 305,206 posts
Athearn DCC Board Replacement - Never Again?!?
Posted by Anonymous on Monday, March 10, 2008 10:09 AM

I'm still a MR and DCC newbie.  I've added 8-pin plug decoders to many of my P2K locos.  I decided to try a board replacement DCC upgrade in HO, prior to attempting any of my n-scale engines.  I was not happy at all with my results and now wonder if I should stick to HO DCC plug n play decoders and n-scale engines with DCC on board/already installed and give up any more advanced work.

I attempted to add a TCS A6X to an Athearn Genesis F unit.  I have no soldering skills but I figured a board replacement without soldiering may be do-able.  I expected the little, black, plastic wire caps to be flexible and easy off and on.  However the caps just would not fit back on the new board and I actually broke one of the A6X boards attempting to replace the wire caps so they would hold the wires on.  I tried widening the black inside of the wire caps, but now some fall off too easily.  Of course after getting it all installed it ran backwards.  Without a system to modify CVs I had to reinstall the board the proper way. 

The engine now runs fine but the headlight/mars light doesn't light up at all.  It was my understanding that this TCS A6X had mars light support and resistors so no additional work would be necessary on the lighting.  Could I have damaged the lights/board when it was in backwards?  My Bachman EZ-Command supports F0-F9.  F0 / F1 usually will turn on my proto headlight/mars lights.  Do I need higher function control and/or CV modification to enable my lights?  Thanks in advance for reading this post and for any assistance you could add.

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Monday, March 10, 2008 10:27 AM

Read the documentation that came with the A6X decoder.  You must program the Mars light function by resetting a couple of CVs, and the lights must be connected to one of the solder pads on the decoder.

The A6X Wiring Diagram on page 7 shows that the mars light function wires must be soldered to pads, and then the decoder must be programmed to activate those pads through CVs 49 through 54.

If you don't know how to perform minor soldering, you need to learn because it's not that difficult.  Otherwise, you'll never get a mars light to work with the A6X decoder.

Even if you do have the decoder properly wired, the Bachmann DCC system cannot program the CVs, so you need to get someone with a better system and some soldering skills to help you install and program the decoder.


  • Member since
    April 2003
  • 305,206 posts
Posted by Anonymous on Monday, March 10, 2008 11:16 AM

Thanks for the responses.  I do have a cheap Radio Shack iron, but my practice and patience ran thin with my early failures.  What type of solder is best to use with this type of wiring? 

I invested in a Zephyr but have yet to complete reviewing the documentation or get it set up.  Work for the future.

I guess I get frustrated with the so called, "experts" at my LHS and show dealers who reiterate how its all plug-n-play, no soldering, and fully usable with my EZ-command, only to find they recommend the wrong decoder (some just would not fit) or it does require additional work and/or CV updates.

I will review my A6X documentation though I recall it only having 4 pages (no page 7), and I was a little disappointed that it didn't help me with my installation questions. 

  • Member since
    March 2007
  • From: St Clair Shores, Michigan
  • 98 posts
Posted by steve58 on Monday, March 10, 2008 1:57 PM

I've used TCS decoders among others and the documentation is ALWAYS a bit confusing to me, regardless of which company it is. Spend some time on the TCS site (and other mfgrs if you use them) and read. Read as much as you can find. Download the pdf files and read them thourougly. I've found that in most cases, the manual that is included with a decoder is pretty basic. To go beyond that, most mfgrs have lots of additonal info posted on their sites that will help a lot.

FWIW, I found the TCS about the easiest to make do exactly what I wanted it to do. It did require that I found the correct docs on their site though.

**** 'course that's just my opinion, I could be wrong ***********
  • Member since
    January 2007
  • From: Wake Forest, NC
  • 108 posts
Posted by Trekkie on Monday, March 10, 2008 2:39 PM
 Tek34 wrote:

Thanks for the responses.  I do have a cheap Radio Shack iron, but my practice and patience ran thin with my early failures.  What type of solder is best to use with this type of wiring?


Speaking from experience, the solder isn't your problem, your selection of the iron is.   Radio Shack has gone from a valuable hobbiest resource to a bunch of cheap chinese crap.

After tossing my cheap chinese knockoff with radio shack branding and getting a weller 35w unit all my soldering problems went away. i'd also recommend getting the 'st7' tip for the iron if you are working on n or ho stuff, it helped a lot for me.    

For n-scale you're going to want the thinnest diameter solder you can find.


My $0.02 

  • Member since
    March 2007
  • From: College Station, TX
  • 673 posts
Posted by Arjay1969 on Monday, March 10, 2008 2:42 PM


The A6X does have the voltage regulator built in for 1.5v bulbs, but you DO have to solder one lead from each bulb to a pad on the board (not the end contacts or the motor contacts, this one is in the middle of the board near one of the long edges).

As for the programming, David is don't currently have that capability with the EZ Command system.  Sounds like you have a good start on that with the Zephyr, though...just take your time and learn your way around the system.  Once you program decoder features a few times, you'll find it gets easier to do (as long as you have the documentation for the decoder!).

Any decoder you install is going to take some soldering work and/or programming to get the lights set up how you want them if you want more than just forward/reverse headlights, in my experience.   It all just takes practice. Smile [:)]


Good luck! 

Robert Beaty

The Laughing Hippie


The CF-7...a waste of a perfectly good F-unit!


Then it comes to be that the soothing light at the

end of your tunnel, Was just a freight train coming

your way.          -Metallica, No Leaf Clover


  • Member since
    July 2006
  • 290 posts
Posted by steamnut on Monday, March 10, 2008 2:44 PM

I've actually just done the same install and I, too am a DCC newbie - my third install in total and my first that was not plug-n-play. It went quickly and easily. After wiring the track power I used micro-hook test probes to determine the correct motor wiring orientation, then soldered the motor wires.

However, I'll agree with you that the claims of both TCS and dealers that this is a "drop-in" replacement are totally incorrect. The TCS soldering tabs are wider than the ones on the existing board. Although I was planning to solder anyway, TCS should include correctly sized plastic wire caps if it wants to claim "drop-in". Also, the solder pads for the 1.5 volt lights are kind of tricky - this coming from someone who is not a soldering "expert" but has quite a lot of soldering experience. Sure wouldn't have wanted to try that as one of my first soldering jobs.

From what I understand, the majority of my diesel fleet is going to require this same approach - replacement of an existing board. Were I you, rather than give up on this kind of install I'd just practice my soldering first. Your soldering iron is fine - just keep the tip clean, I use an old foam rubber cleaning pad with a bit of water poured on it. Get 60/40 electrical solder in a smaller wire diameter, do some practicing, and you'll be in business in no time. Unless you decided to return it, you might want to practice with the pads on the decoder you broke. On the other hand, you might find it easier to use dropping resistors and more "standard" drop-in decoders - then you can solder to the 12-volt soldering tabs as opposed to struggling with these pads.

  • Member since
    January 2004
  • From: Tarpon Springs, FL
  • 331 posts
Posted by cmarchan on Tuesday, March 11, 2008 7:41 AM

I dont like the term "drop in replacement" because a lot is assumed here. A better term is "replaces existing light board without frame or shell modification". Until the A6X was made, the other Kato / Genesis replacement board decoders required either voltage regulation or current limiting resistors for the lamps; Genesis locomotives typically use 1.5 V, 12 ma (milliampere) lamps.

Best Practices:

1. Read the instructions carefully - don't trust what you've heard about how easy it is; you will hear a lot out of context.

2. Buy a good soldering iron and good solder - I personally recommend a low cost variable temp iron and Kester solder (thin solder, one pound spool). This will give you the best results in any DCC decoder install. Dont use the price as your deciding factor; check with a local electronics professional (not the Radio Shack employees!). Also invest in a bottle of resin flux or resin paste.

3. Forget about those darn plastic caps - most of the decoder boards are thicker than the light boards they replace; if you learn to solder, you will make a better connection one time. Intermittent connections can cause erratic operation or even damage the decoder.

4. Soldering - Practice, Practice, Practice, - when I taught electronics, my students spent a week practicing soldering. Learn the nuances of the iron, how to tin wires and join them together; practice soldering on the old light boards.

Remember, this is like any other aspect of this hobby. Whether you are learning to lay track, apply scenery, painting, decaling, or weathering rolling stock, patience and practice and a little research goes a long way.


Carl in Florida - - - - - - - - - - We need an HO Amtrak SDP40F and GE U36B oh wait- We GOT THEM!

  • Member since
    October 2005
  • 79 posts
Posted by ianalsop on Thursday, March 13, 2008 5:57 PM

Carl's right - get some flux - it'll change your soldering for the better.

I use a paste and apply a small amount to the solder pad using a wooden toothpick or cocktail stick.

Connect only the two motor leads and the two pick up wires before testing (and don't put the loco shell back on yet). If there's something wrong you've less wires in the way to correct the problem. Then connect one of the lights and re-check and so on.  

I've 10 locos with A6X's in and they're all fine runners.  


  • Member since
    April 2003
  • 305,206 posts
Posted by Anonymous on Sunday, March 16, 2008 8:43 AM

Thanks for all the help and encouragement.  I did get the two forward light wires soldiered to their pads.  I also programmed CV49 & CV50 with various values (0,2,34,45) though it seemed even with the default values for any of the CV49-V54 values that I should be seeing some kind of lightning effect.  No?  Still no light.  Do I need to activate the function (F0) for CV49/CV50 or enable any other setting to turn this on?

Do I need to add a resistor and if so what size?  I thought I was told with this particular decoder that it was already built in and I would not need to add a resister.  If so is 680 ohm adeqate?  Is 1k ohm better?  Does this envolve splicing into the light wire or simply soldiering an additional wire to the same pad?  The wiring diagrams packed with the decoder incorporate the reverse light wires.  This particular engine has no reverse lights or wires.  Do I still need to wire something to the reverse light tabs even though nothing was there with the orginal board?  Will radio shack have appropriate resistors?  Sorry for all the questions, but while online information is available they also seem to assume a further level of knowledge about what you are doing and some is contradictory. 

  • Member since
    October 2004
  • From: Richmond, Texas
  • 393 posts
Posted by RDG1519 on Sunday, March 16, 2008 11:13 AM

Take to heart the guy's who are talking about flux. It is what transfers heat, prepares and cleans the surface etc. I use flux out of a "tin" and generally do not use solder that has flux inside it. Also remember the iron heats the surface being solderered, the hot surface melts the solder. Heat the ehaviest surface first. Also tinning wires and lands is helpful.


Great grandson of John Kiefer, Engineman Philadelphia and Reading Railroad, 1893 to 1932
  • Member since
    January 2001
  • From: US
  • 154 posts
Posted by greendiamond on Wednesday, March 19, 2008 2:36 PM

I sell TCS decoders, as well as other lines.  John at TCS gives you a one year goof proof warranty, even if you messed the decoder up.  Just drop him an email or phone call.  The TCS A6X has a built in voltage regulator on board and works very well with the Athearn Genesis engines that use 1.5 volt bulbs, but you will need to solder them in on the board. 

Your F0 will control the on and off of the headlights. If you soldered the lights to the correct places, no resisters will be required.  If you hooked them up to the 12v contacts and turned them on, they were on for a very brief moment before they burnt out.

If you don't have a back headlight, you don't need to hook anything up to the connection on the decoder.

Soldering is a needed skill when working with DCC and you only get better with practice.

In HO, unless it's a plug in decoder with the 8pin plug or the 9pin JST connector, you will be soldering.  As in a previous reply, the decoder boards are usually a bit thicker that the original light boards they replace.   Some decoders are easier to solder to because they have larger pads on which to make your connection.  The A6X is one of the easiest on the market.

If you engine runs backwards from the lights, you can either switch the orange and gray motor wires, or if you can program CV29, just put a '1' in that location or add a '1' to the value in it.  (Use your Zephyr for that), since you can't program with the Bachmann unit.

I do sell DCC at some train shows around the midwest and regularly at Wheaton and all I can say about your experience with DCC is that you need to develop a relationship with a good dealer. You need to take the time, to get your questions answered.  Especially at train shows, there are times when there are crowds and a customer asks for a decoder for a locomotive and the proper one is sold without much if any additional conversation and the next customer is taken care of.  I have customers who will only by from me because of the relationships we have developed.

The A6X is the way to go for your engine in my opinion.  Others may disagree.

In N scale, if you're leary about doing installs, then pick up the locos with the decoders already in them.  However, most of the newer locomotives have been designed for very quick decoder installation.  Remember, I said 'most'!  Most are just slip the shell off. Losen the two frame halves, slip the light board out and the decoder in.  Again, that's 'most'.  Some N scale installs are a nightmare, depending on the locomotive, your patience, skill level, size of your fingers and quality of your eyesight.

Relax. Take your time.... and develop your skills.  We all make learning mistakes.  Some are more costly than others.  I don't think theres anyone who's installed decoders, who hasn't messed one up.  Welcome to the club!

Above all keep having fun!

Mike Tyl 

  • Member since
    February 2006
  • From: SW Wisconsin
  • 158 posts
Posted by 60YOKID on Thursday, March 20, 2008 10:00 PM

All good advice above.

However, I prefer rosin core kester 60/40 solder in a very fine wire size, about the size of a #16 solid copper wire.  I also use a little soldering paste or flux. Just touch the wire into the paste because all you need is a tiny amount.

Never use acid!

I also suggest a good temperature controlled iron with a small tip.  I put the solder between the tip and the connection.  The solder will melt and transfer the heat quickly to the connection.  As soon as the solder flows into the connection, take away the heat quickly.  And presto, you will soon be getting nice shiny connections.

Link to Weller soldering station

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Search the Community

Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!