I have a Kato DCC ready “Dash 9” locomotive that I use pretty reguarly. I bought it new off E-bay a little more than a year ago and in that time, it has melted two decoders. They’ve both been Digitrax. I’ve tried searching for answers, but haven’t really found too much.
Is there something I should check for or do to prevent this from happening again? Attached are pictures of the decoder for that its worth. You can some marks on one of the pins which I believe connects to the red wire on the harness.
It sounds like what you are encountering is too high of a current draw than the decoder can handle.
Do you have a way to bypass the decoder (dummy plug) or temporarily remove the decoder and use an ammeter to measure just how much current the motor is drawing. You should also measure the stall current.
Some of the earlier decoders required more air space around them, too. If your engine is drawing close to 1 amp and the decoder is mounted close to the motor there may be too much residual heat that may not be able to dissipate.
Look for any binding in the drive train, be sure lubricants are not too gummy. Apply a tiny drop of fine oil to the motor bearings.
If none of this helps you might resort to looking for a decoder with a slightly higher current rating, but for a Kato loco the current draw should certainly be more in the 400-500 milliamp range, well below the max for a DH126.
Lastly, it may be possible the motor is simply worn out, or at least the brushes are.
Liquid electrical tape, actual electrical tape, double sided foam tape or Kapton type ESD tape on the back side of the decoder or its pin connection may be needed.
Sounds like something about your installation is resulting in a short to the locomotive frame or some other metal connection grounding the decoder or touching two contact points on the decoder or its plug. Examine that installation and try to imagine how that might be happening. Examining the bricked decoder for signs of a source for the shorting might help identify the problem.
Sounds like someone did not do a proper conversion to DCC. I bought a Kato NW2 off e-bay with DCC and even though I have not had a proublem yet, if they did not do the conversion properly and it derails it will need a new dercoder.
I agree about the amps, that’s what I would check first. There is no mention of short circuits, so it’s unlikely to be the problem. I have installed dozens of Digitrax decoders, and only one has failed, by my own fault.
What I find intriguing is the fact that the loco is described as “DCC ready”. Installation should be straigthforward and pretty much any decoder should meet the amp draw. What type of Digitrax decoder did you use? Was the engine operating normally in DC mode?
Well do remember the factory install dcc of Kato’s sd80 Mac. That little tab that fired and shorted many decoders. Could this be a similar issue. A small factory created short somewhere? Ab bad factory wiring isn’t out of the question
shane
We can’t see your embedded pictures so we don’t know which version of the DH-126 you are using and what the decoder looked like after it melted. I would think that is a 8 pin install since the that is what is specified in the Digitrax decoder selection tool.
Before each decoder melted, did you get a chance to check if the decoder became hot on a regular basis after use? If it gets hot after each use, then the suggestions about motor amperage are most like the main issue. If it does not get hot after each use, then I would suspect some type of short.
Says he runs them all the time and that they melted. Also says nothing about factory installed DCC ready or what that even means as many manufactures have in the past said that only to find it not to be true.
I have one Kato locomotive that is “DCC ready”. It is absolutely not a “Dash-9” anything.
It does not have an NMRA 8 pin plug. I think the Kato term “DCC ready” (in this instance) just meant the motor was isolated from the frame and there was a slot machined into the frame halves for space to mount a decoder.
Kato DC locomotives were a challange to convert to DCC because the motor was sandwiched in between two frame halves. These frame halves were both part of the electrical circuit to the motor. Isolating motors from these frames was very difficult.
Since this is just one locomotive, I have no way of knowing of this is typical of the majority of Kato models or not.
I had a few early Life-Like PAs that had motors that would normally run close to 1 amp but when stalled the current would jump to 3 to 4.5 amps. Life-Like chose motors with the wrong specs.
How things change. I remember reading on these pages years ago, probably in this very forum, that there was no consensus about exactly what was meant by “DCC Ready.”. Most of the engines I’ve purchased with that label had no plug for a decoder, and required a hard-wired job. At first, I bought non-sound decoders with just wires, no plugs, and just wired them in.
I bought one of these DCC Ready locomotives from my LHS. The owner took the engine apart for me and showed me what I had to do before installing a decoder. I think it was something with insulating the headlight bracket. I did that and never had a problem.
As I recall, it would only be a problem if a particular derailment caused an inappropriate current to flow through the locomotive.