# mth problem



## riogrande51 (Aug 24, 2012)

Just pick up a used but very good shape I through MTH SD 70 ACE Looks and sounds great runs great for about five minutes until it gets hot then it stops for a split second then starts again about every 3 to 4 feet.
I have reset it back setting the loco to 55 CV 55 to 55 it goes back to address #3 BUT STILL WILL STOP AND GO WHEN IT RUNS FOR A FEW MINUTES 
ANY IDEAS??
THANKS




RIO GRANDE 51


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## CTValleyRR (Jul 26, 2014)

MTH uses a proprietary DCC system that is not compatible with the NMRA DCC standards. If you're not running a DCS system, you will need to replace the decoder with an NMRA compatible one.


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## D&J Railroad (Oct 4, 2013)

CTValleyRR said:


> MTH uses a proprietary DCC system that is not compatible with the NMRA DCC standards. If you're not running a DCS system, you will need to replace the decoder with an NMRA compatible one.


I don't think that would be the problem. The SD70Ace has a DCS decoder but the basic functions are compatible with DCC. It should be able to hold a 4 digit address and work the lights, direction and speed. Your problem of the model starting and stopping is certainly a problem in the drivetrain. Have you opened the model to inspect the motor and drive train for obstructions?
You said it was used. If you got it off of ebay, I would suggest you immediately contact the seller and tell him of the problems and be prepared to send it back.


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## CTValleyRR (Jul 26, 2014)

D&J Railroad said:


> I don't think that would be the problem. The SD70Ace has a DCS decoder but the basic functions are compatible with DCC. It should be able to hold a 4 digit address and work the lights, direction and speed. Your problem of the model starting and stopping is certainly a problem in the drivetrain. Have you opened the model to inspect the motor and drive train for obstructions?
> You said it was used. If you got it off of ebay, I would suggest you immediately contact the seller and tell him of the problems and be prepared to send it back.


Obviously, I have no personal experience with the DCS stuff, but there was a long discussion on a different forum about this, and it did turn out to be the decoder.


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## gunrunnerjohn (Nov 10, 2010)

It depends on the vintage of the locomotive. The early MTH HO DCS/DCC stuff had very limited compatibility. The last couple of years they have gotten much better.


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## D&J Railroad (Oct 4, 2013)

gunrunnerjohn said:


> It depends on the vintage of the locomotive. The early MTH HO DCS/DCC stuff had very limited compatibility. The last couple of years they have gotten much better.


I think their latest locomotive have standard DCC decoders. I looked at their web page and that is the going feature now.


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## riogrande51 (Aug 24, 2012)

*MTH more problems*

Well I tore into the loco to try and find out what was going on and now I got real problem while removing the weight and decoder the three wires to the motor got broke off they are very close together so when you solder one the other one comes off and you get soder on more than one any suggestions other that sending it back. Is there a way to solder wire when it is close to one another?


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## DonR (Oct 18, 2012)

Would it be possible to use a plastic shield of
some sort between the tabs?

Perhaps you could use a tweezers as a heat sink on adjacent terminal.
I have inverse tweezers (I forget the correct tool name).

For a solder job on what you seem to indicate is a very
small tab, I would make sure it is 'tinned' and also
that the wire end is. Hold them together and carry
a tiny dab of solder to them with a sharp point
soldering iron tip. Just a touch should be sufficient.

Don


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## riogrande51 (Aug 24, 2012)

Fixed the whole problem complete gut of the MYH and installed a Soundtraxx Sound Decoder problem solved
Thanks 





Perhaps you could use a tweezers as a heat sink on adjacent terminal.
I have inverse tweezers (I forget the correct tool name).

For a solder job on what you seem to indicate is a very
small tab, I would make sure it is 'tinned' and also
that the wire end is. Hold them together and carry
a tiny dab of solder to them with a sharp point
soldering iron tip. Just a touch should be sufficient.

Don[/QUOTE]


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