I just turned on my Athern DC controller (i dont use DCC because i am cheap) and for some reason after turning it on my Dash 9 just runs away at half spead, i can control the reverser and i can only make it go faster. Can someone help me resolve this issue?
Welcome to the forums.
Sorry to hear you are having problems, but they happen. I haven’t had the problem, so may not be much help except to get you back to the top of the page for others to see.
Am I correct in understanding this in an Athearn brand controller? Does it have a model number, to help folks out? When did it start doing this? Is it new and always done it or did it used to work OK and has recently started doing this?
If it is new, contact Athearn for a warranty replacement.
If it is not new, my first thoutht is that the controller has somehow fused the lower speed sections together. I’m no electrician, but having seen the insides of similar things, I’d say it is a possibility.
Do you have a multi-meter to check the output of the controller?
Do you have another loco to use as a test or a friend to borrow one from?
Do you have another controller, even a small one from a set you could use to check and see how the loco responds to it. You could also take your loco to a friends layout or a hobby shop to see how it runs there.
Hopefully someone else will have some more specific information for you.
Good luck,
Richard
Also, does the loco behave on straight DC without the controller (assuming it has a dual mode decoder)?
Hi George:
If I read the OP’s post correctly he is having the run away problem on DC. He said he doesn’t have DCC .
I think Richard pretty much covered the bases. Having a second locomotive to test the power pack with would immediately tell you where the problem is. I’m betting the power pack has a short.
Dave
If the power pack had a short…it would not work at all.
My guess would be the potentiameter went south, (throttle control) they are not the best on a trainset transformer, which My guess, that’s what it is. Best to just get a better one. You can test it if you have a multimeter. Leads go to variable DC output, should have no output, until you turn throttle. You may even be able to feel a restriction, when you turn the knob. It probably doesn’t have very much power output either, so I would not even use it for acc’s either.
Take Care! [:D]
Frank
Sounds like a power pack (controller) failure. On DC, the throttle varies the voltage to the track, from 12 volts for full speed, down to 0 volts to come to a stop. With zero volts on the rails, the locomotive is gonna stop, no conceiveable locomotive failure can make it move without power.
At a guess something has failed inside the power pack and the output voltage is just fixed, turning the throttle doesn’t change it. You can check this if you have some way of observing the track voltage (volt meter or even just a 12 volt light bulb). Check that the track is connected to the VARIABLE DC output and not the FIXED DC output. Powerpacks usually have variable dc to run the trains and fixed dc to operate accessories and switch machines. If you somehow get the fixed and variable dc outputs mixed up, it could account for your problem. It’s worth checking.
If your powerpack is one of those little trainset jobs, only a couple of inches long and wide, you might want to just buy a good MRC power pack. They will give better low speed operation, they have enough juice to power a four unit diesel lashup, and will last forever. Cost $50-$75 new.
So Frank:
Pardon my miss-use of the term ‘short’, but if the locomotive starts off fast when the throttle is first opened wouldn’t that indicate that there is a ‘short’ in the lower range of the pot?
I guess I’m splitting hairs.
Dave
LOL…It would be an open. If a short…+ touching - it would not work at all. I’m pretty sure it is the pot in his controller.
Take Care! [:D]
Frank
Wouldn’t any “open” winding create a no power on all throttle position/ Or any short would short regardless of throttle position.
Bob,
I believe You are correct on the below statement.
My guess what is happening, the wiper lug is not touching the beginning winding where most of the resistance is, so no speed control. Someone also could have tried to turn the knob too far in the high speed direction so it knocked the lug out of center. Seen that happen before with a friends kid do it, same thing as the Op’s but not quite that high speed, He just could not stop it.
Take Care! [:D]
Frank
Wouldn’t any “open” winding create a no power on all throttle position
It is an Athern transformer. the model # is SDK-789. I have been using this in the past few years, but it has been working like a champ until just now. This just started happening since Saturday. i do have several other locos but they all had the same result. I do have a multiplier and i do have another transformer that’s a Bachmann (that small square ones.) and the locos run fine on it.
Gentlemen, it is a SDK-789 model and i have used it for several years and it has ran like a champ before this problem occured. i have tested all of my locos on it and all of them have had the same result.
Sorry for the two posts saying the same thing, not used to this reply approval system.
Frank and Bob:
I think you guys are pickin’ on me[:'(].
I used the term ‘opening’ to mean turning the throttle up, not in terms of electrical continuity.
Anyhow, the OP’s last posts pretty much establish that the power supply is toast, no doubt for exactly the reasons you state.
Aval5: My suggestion is to cut the cord off. Then you can use the power supply as a very nice paper weight[swg][(-D].
Dave
Sounds like a great idea 
Dave,
I twern’t pickin’ on You…I was disssgreeing with a short. [:(]
I believe also He should get one that has more power…trainset one’s don’t.
Take Care! [:D]
Frank