atlas decoder trouble :confused:

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emt49

internets worst speller
i just got a atlas GP40 DCC loco and am haveing some trouble with it . it runs fine in dc mode but when put in dcc mode it gets all funky on me. when i put other locos on the track with atlas decoders and try to mu them as soon as the other loco gets close to the GP40 it takes off down the track even if its set in revrise it moves forword away from the other loco. but heres what stumped me it only dose it with atlas decoders i have a number of diggi traxs decoders in locos and it runs fine around them it just seems to behaveing a problem with other atlas decoders. any thoughts or maybe a fix to this porblem ?
 

grumpybob

Lake Shore Lines
I hate to say it, but in all the years I have had DCC, the biggest decoder problem has always been with the Atlas decoders. They either take off like a rocket, and can't be controlled, or they have a flame out. I would suggest that you call Atlas and see if they can help you. Otherwise, I would replace the decoder with something comparable from TCS, Digitrax, or NCE.
 

HaggisKennedy

Coal Shoveler
I've never really had problems with any of the Atlas locos I have. They all seem to play nice with each other. Is this one of the newer locos?

It could be a bad decoder, but maybe you could do a reset and try it again.

I'm also trying to figure out if your problem is during the consisting, or when two separate locos are next to each other and aren't MU'd.

Also, what DCC system are you using?

Kennedy
 

emt49

internets worst speller
well it's new it has the 4 function decoter in it its a susquehanna GP40 and decoder dose not like to play with other of its kind . Digitrax decoders it has no problems with its just other atlas decoders
 

HaggisKennedy

Coal Shoveler
Very strange. I'm stumped, right now.

The only thing I can think of is that the speed curve, or start voltages, etc., are way off from the other Atlas ones. I say this based on the presumption that when you MU two atlas locos to one consist addy, and increase the throttle, the one runs differently than the other.

If you're saying that when you run your GP40 by itself, and as it passes by another Atlas loco (say, a GP38), the GP40 goes out of control, then I'm baffled.

Having said that, I've MU'd an Atlas B40-8 to a GP60B and GP60M (both with TC-1 decoders), and it took awhile to get their speeds together so they'll play nice. Conversely, I put a GP40 and a GP38 together, and they were OK out of the box....

I'm thinking speed curve, start/mid/max voltages, speed step mismatch as possible causes.

Kennedy
 

HaggisKennedy

Coal Shoveler
Ok, as I'm sitting here after eating lunch (and contemplating a nap), let me see if I can rephrase the situation where you're having a problem. Mainly because when I read your initial post, I get about 15 different versions of the situation. I just re-read your initial post, and now I seem to think that you're trying to consist your locomotives while they're moving.

The other alternative the way I read it is you're moving the locos close together so you CAN mu them (consist them), and the GP40 goes wild.

The third way I read this is you are trying to run them on their own addresses, and when they're close, the GP40 goes out of control.

What I *THINK* you mean is that you put your GP40 onto the track next to another atlas decoder equipped loco. You consist the two, and when you try to move the consist, the GP40 does something different. Though I kind of wonder about this because you say the GP40 works with the other, non Atlas locos....

:D

Kennedy
 

emt49

internets worst speller
this is what happend i have a atlas master GP40 with the 4 stage decoder. i also have a GP38 atlas master with the same decoder. i gave them both a diffrent address put them on the same track and tryed to back the GP38 up to the GP40. but when the GP38 gets close to the GP40 the GP40 starts moveing away from the GP38 without anyone touching the controller for the GP40.

if i set them them up mu nose to tail or elaphant style as i think they call it the GP40 wants to move away from the GP38 even thou they are both set up to run forword. now i also tryed this with a U30 atlas master and the GP40 acts the same as above.

but when i put a loco with a Digitrax decoder in it the GP40 acts as it should i have no problems.

i have the Digitrax empire bulder with the DT400
 

HaggisKennedy

Coal Shoveler
That's really weird. What you're saying is at with the GP40 at Speed Step 0, when the GP38 gets close to it, the Speed Step of the GP40 goes to 1 or more.

What that also says is that somewhere, something is telling the GP40 decoder to go to Speed Step 1.

You probably already know this, but the way DCC works is that the command station says LOCO GP38, run at SS 1+. In order to move the GP40, the command station has to say LOCO GP40, run at SS1+. If nobody is touching the controller for the GP40, then something else is telling LOCO GP40 to move.

Which basically means that LOCO GP40 is acting on instructions meant for somebody else. Never heard of that before. 'Tis a puzzlement.

Try this. I presume you have two DT400s? Try releasing the GP40 from all of your throttles. In other words, the GP40 should not be assigned to any throttle at all. See if your problem still happens.

I'm thinking that the GP40 has been acquired by some other throttle, or still is assigned to some other throttle..

Kennedy
 

emt49

internets worst speller
HaggisKennedy said:
That's really weird. What you're saying is at with the GP40 at Speed Step 0, when the GP38 gets close to it, the Speed Step of the GP40 goes to 1 or more.

What that also says is that somewhere, something is telling the GP40 decoder to go to Speed Step 1.

You probably already know this, but the way DCC works is that the command station says LOCO GP38, run at SS 1+. In order to move the GP40, the command station has to say LOCO GP40, run at SS1+. If nobody is touching the controller for the GP40, then something else is telling LOCO GP40 to move.

Which basically means that LOCO GP40 is acting on instructions meant for somebody else. Never heard of that before. 'Tis a puzzlement.

Try this. I presume you have two DT400s? Try releasing the GP40 from all of your throttles. In other words, the GP40 should not be assigned to any throttle at all. See if your problem still happens.

I'm thinking that the GP40 has been acquired by some other throttle, or still is assigned to some other throttle..

Kennedy

yes thats what happens but the GP 40 only moves a foot or so then stops till the GP38 gets close agen

as for the throttle i only have on throttle its normely just me running my layout. but i was thinking of getting a ut throttle or 2 incase i ever have someone that wants to run them with me

thanks for all your replys maybe ill just call atlas and see if they will send me another decoder or ill get a Digitrax one and replace it
 

HaggisKennedy

Coal Shoveler
Have you posted this on the Atlas forum, or Digitrax Yahoo list? Or any of the general DCC lists on Yahoo? There's some knowledgeable folks there, though the Digitrax one sometimes will come across as condescending. But, I suggest them since you have the EB.

If you haven't, I might ask for you, or on one of the other lists I'm on that's friendlier....

Kennedy
 

jasonboche

New Member
I sometimes had the problem of "runaway locos" on my Digitrax Zephyr system. One thing that I do is to disable DC on all my locomotives. This can help prevent the runaway condition. Essentially what this means is that the locomotives will not respond at all to DC current, only DCC commands.

Jas
 




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