Re-Programing Decoders

SD90 Oct 30, 2011

  1. SD90

    SD90 TrainBoard Member

    156
    0
    14
    I installed the new decoders in my 4 new AC4400's, and than noticed that I needed to speed match all of my other locomotives to them. They way they were was too slow, so I had been running on the HO setting on the Digitrax system. I'm now in the process of speed matching all of my locomotives to the new ones. I set the CV's of the new AC4400's to the following. CV2=1,CV6 (mid voltage)=25, and CV5 (high voltage)= 65. I'm amazed at how my old AC4400's have mid voltage settings from 60-80 and high voltage from 120-155, to go the same speed as the new ones!
    I'm wondering if this means I need to oil the gears on the ones that need such a high setting?
    Anyway, it is a daunting task that must be done!
     
  2. DCESharkman

    DCESharkman TrainBoard Member

    4,396
    3,025
    87
    This is why using speed tables with Digitrax decoders is much easier. Digitrax is one of the few manufacturers that implement TRIM and that makes speed matching a snap. You could adjust the trim on the new units to speed them up to match the existing units.

    What is puzzling is that the new AC4400's are slower than the older ones. I have them from every release and have not seen that happen. It may be that you need to do a factory reset of the decoders a couple of times and then reprogram them, or you may want to run them a little while longer on DC to break them in a little more.
     
  3. rrjim1

    rrjim1 TrainBoard Member

    821
    12
    15
    I purchased two Atlas Train Masters at the same time, ran them on DC and they ran real nice together, figured no speed matching needed. Installed new Digitrax decoders and one ran fast the other really slow? I reset both decoders and problem solved. No speed matching needed.
     
  4. SD90

    SD90 TrainBoard Member

    156
    0
    14
    How do you use the trim function? I've never heard of that.
    I'm using one engine, MU'ing another to it, and running it down a straight track to see how much to adjust the mid and high voltage to match the first engine. It is time consuming, if there is an easier way, I'm open to suggestions!
     
  5. DCESharkman

    DCESharkman TrainBoard Member

    4,396
    3,025
    87
    First you have to use the 28 step speed table, Trim is not enabled unless the speed tables are used on Digitrax decoders.

    Then, it is a matter of adjust CV66 for forward trim, and CV95 for reverse trim. I went through this in detail in the DCC forum, if you search over there, you will find a lot of good information.
     

Share This Page