Decoder manual for DCC Atlas GP-9 ?

Discussion in 'N / Z Scale Model Trains' started by Biased turkey, Jul 17, 2008.

  1. Biased turkey

    Biased turkey Active Member

    Last week-end I took the DCC plunge and purchased one MRC Prodigy Advance2 system + an Atlas GP-9 DCC equiped N scale engine.

    After fiddling for about 2 hours I was able to have the engine running . I'm not completely satisfied because I can't adjust the starting speed: the engine starts to move only when the throttle knob is at the position 8.
    The Configuration variable CV# 2 ( SV or Start Voltage ) was factory set to 8 so I reprogrammed it to a value of 1 but that didn't fix the problem.

    There is no information about the decoder enclosed in the engine plastic box ( 1 bad point for Atlas ).
    Does any member on the N scale subforum , who has the same engine , know a place where I could find that information ?
    I checked Atlas subforum , but to no avail.

  2. seanm

    seanm Member

  3. Biased turkey

    Biased turkey Active Member

    Thanks seanm for taking some of your time to reply. I too checked the document at the link you mentioned. For the GP-9 it only mentions the Atlas part # 470299, but not the decoder chip part #.
    I downloaded the pdf manual of the LE063XF used in most of all the other engines. By default, CV#2 ( start voltage ) is set to a value of eight. I reprogrammed that value to 23 and now my engine starts as soon as I rotate the knob to position #2. At least it's better.
    As you says, my best bet is to contact Atlas.

    I was noticed by email from The Gauge that UP SD40-2 ( Deano ?? ) replied to my post, but his reply doesn't appear on this thread, so here is the reply:

    Jacques, i am sorry, i don't know the CV# to change the speed curve on that particular engine, but i will tell you this, it is VERY NORMAL for DCC engines to start moving at different speeds<img src="./mysmiliesvb/mysmilie_57.gif" width="16" height="16" alt=":winki:" /> . few of the over 80 DCC engines i have start at the same speed, much less at exactly at 1mph<img src="./mysmiliesvb/mysmilie_57.gif" width="16" height="16" alt=":winki:" /> .

    different decoders, matched up to different motors along with a multitude of other variables makes getting every engine you have to start at 1mph in any situation(up hill, etc. ) a daunting task. i am sure it can be done, but it never bothered me enough to go through all the hassle to change the speed curve on all of the engines i have. i look at it like this, NONE of my DC engines EVER started at exactly 1mph, it didn't bother me then, so it doesn't now<img src="./mysmiliesvb/mysmilie_57.gif" width="16" height="16" alt=":winki:" /> ...but thats just my thoughts<img src="./mysmiliesvb/mysmilie_34.gif" width="15" height="15" alt=":119:" /> .

    i hope someone with that type engine has your answer:thumb: .
  4. UP SD40-2

    UP SD40-2 Senior Member

    Jacques, i should clear up the point i was making, when i wrote earlier, then deleted it.

    I FULLY understand wanting to get your engine to start out at exactly 1mph:winki: , thats tough to do in every situation though:frowns: , Charlie hit the nail on the head with one example:winki: .

    Lets take my Intermountain cab forward for example, i put a sound decoder in this engine, and it started moving at 12mph, so it read on the throttle, the chuff rate was wrong too:roller: . i decided to get this engine "right", so i spent well over an hour adjusting the speed curve & start voltage CV's, the best i could come up with was getting the chuff rate right, but the engine by its self started moving at 2mph. after adding cars to it, depending on the amount i added, the speed would go up, but the engine wouldn't move till a higher speed, though the chuff rate was still good.

    i don't take much stock in going by the speed that shows up on the controller/throttle:roller: , i can turn my cab forward up to 128mph, well, thats what it says on my controller:119: , but in reality the engine tops out at 40-45mph, regardless of what the speed on the controller says:winki: .

    hey, i can understand wanting to get the start speed "right":thumb: , but i think it would drive someone bonkers trying to get an engine to start moving at exactly 1mph, in every situation(added cars, up grades, etc. ). getting it closer then it is if its way off is always a good thing:winki: , but don't get discouraged if you cant get it "right on" every time:winki: . and don't take alot of stock in the speed the throttle/controller says either, i have engines that start moving at the same speed, but when they hit, lets say 40, one of them is clearly running faster or slower then the other...unless you ran them in a consist, but thats a whole other ball game:119: .

    JUST MY THOUGHTS:smilie:
  5. Biased turkey

    Biased turkey Active Member

    Thanks Charlie and Deano for taking some of your valuable time to supply some additional information.
    I agree with Charlie that the definition of "Staring Voltage" might be confusing, it is particularly true with the definition from the MRC manual. But the Lenz LE063XF ( used in most Atlas N scale engines ) decoder manual has a clear definition of Sv:
    2 2 Start voltage:
    This is the voltage applied to the motor in speed
    step 1. Set this value so that the locomotive just
    starts moving in speed step 1.

    Deano, I don't want the engine to start exactly at knob position 1 ( I'm not a knob position counter ), but when the engine starts only at position 9 or higher it is not very realistic.

    I think I found the right Start Voltage value ( 23-24 ) and it is way higher than the default value of 8.

    All in all, I'm now satisfied with my MRC system and my new Atlas GP-9.

  6. Biased turkey

    Biased turkey Active Member

    Thanks again for the help Charlie. We like your positive attitude here, even if you are not back to modeling ( yet ) you still keep in touch with model railroading and help your fellow modelers.
    As suggested by seanm I contacted Atlas today so we'll get ( I hope ) the information straight from the horse's mouth.

  7. Biased turkey

    Biased turkey Active Member

    All right, let's hear it straight from the horse's mouth.
    Today I received the reply from Atlas.
    Jim Miller kindly replied to my enquiry, here is a copy of the e-mail:



    I apologize for the confusion. We may need to update our website.

    Most Atlas N scale decoders, including the one you asked about, use the same CVs as the Atlas LE063XF decoder. Hence, I am attaching a PDF file containing the LE063XF user manual.

    Atlas cannot fit a decoder user manual in an N scale locomotive box. Hence to get a manual, you need to go to the Atlas website , select first “Support,” then “Manuals,” and finally double click on the manual you want.

    All of our current N scale decoders were designed by Lenz but are manufactured, sold and supported exclusively by Atlas.

    Your English is much better than my French since I last studied French as a college junior many years ago.

    Jim Miller

    Atlas Model Railroad Co., Inc. and Atlas O, LLC

    378 Florence Ave.

    Hillside, NJ 07205


    (908) 687-9590

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