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Replacing an MTH DCS decoder

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  • Member since
    December, 2018
  • 1 posts
Replacing an MTH DCS decoder
Posted by espeedcbc on Monday, December 31, 2018 2:45 PM

Can anyone advise on replacing the MTH factory decoder in an HO GP-35?  I love the loco, but it seems since I have an NCE Power Cab system, the DCS in the loco is more difficult to deal with.  My Athearn Genesis and BLI locos run great.  I just need some advice on dealing with the MTH DCS equipped loco.  I am fairly new to all this but I am pretty sure I am capable of changing a decoder if that is the way to go.  Thanks for you comments.

  • Member since
    May, 2010
  • 5,477 posts
Posted by mbinsewi on Wednesday, January 02, 2019 3:18 PM

I think you should look to MTH, check out their web site, see if they have a servicing or troubleshooting section, you know, repairs, adjustments, replacing parts, manuals, etc.

Your problems are like others in here that have tried to run DCS with DCC.

Mike.

  • Member since
    February, 2002
  • From: Reading, PA
  • 26,418 posts
Posted by rrinker on Wednesday, January 02, 2019 5:18 PM

 My problem with my MTH FAs doesn;t really have anything to do with running the DCS loco on DCC, the control is fine. What are yoou trying to do to it, outside of changing the address to the cab number? My real issue with the thing is that if there is a power interruption, the sound cuts out, and needs the F key to turn it back on. Fine, except if the sound cuts out on just the A and not the B, hitting the F key starts up the A but shuts down the B. 

 Replacing the decoder is not simple, because in yet another BRILLIANT (that's sarcams, son, sarcasm, i say) engineering move, the LED lights in MTH locos use a NEGATIVE common. DCC is POSITIVE common. Since the LEDs are all on little circuit boards in the loco, you have to replace all those with individual LEDS (in some cases you can cut traces on the light boards and rewire it). Bottom line is I will probably just get rid of the MTH locos and put sound decoders in my P2K FAs, an easier task.

                                          --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    April, 2019
  • 4 posts
Posted by Trains213 on Wednesday, May 29, 2019 2:50 AM

The other poster is correct you would pretty much need to rewire the engine completely

 

rrinker the super caps on your unit are faulty, this is very common on MTH HO engines, you can get them from a electronics supply store for under $10.00 probably. I don't have the part number since I left MTH but I bet that would solve your problem or you could send them to MTH and have them replaced for $59 plus shipping, but since they are F3's they probably have the junk motors and probably wiring issues, it is very common on these engines, I always told people to send in both engines when they had HO Alco's and I rebuilt them both, but that probably doesn't happen anymore since everyone else there was more interested in doing anything but work. They lost the same $40,000 worth of trainworld engines 4 times while I was there. I also don't trust the work their technicians do.

  • Member since
    February, 2002
  • From: Reading, PA
  • 26,418 posts
Posted by rrinker on Wednesday, May 29, 2019 12:09 PM

 I can check them, but these were BRAND NEW. Hard to figre there are failed super caps in BOTH unused units. They aren't that fragile as far as electronic components go. Mine are FA Alcos, not EMD F3s.

 If - IF - I keep them, they are getting Loksound decoders. There's not a whole lot to rewire as I can simply skip the gimmick red/green class lights, and all I need is a headlight. Rather than rewire it I would just add an LED in the A unit and remove whatever board MTH has in there. I put the Kadees in for the couplers not long after takign them out of the box, the remote uncoupling is also just a gimmick. Great, I can drop my entire train - and have to hit it at ramming speed to get the couplers to close back up.

People with the more modern locos with ditch lights and all sorts of extras liek that have a much harder job of it, lot more lighting to repalce.

The whole common negative, switch the power just tells me whoever is the supposed engineer designing their circuits has little knowledge of modern embedded electronics.

                                    --Randy

 

 

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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