Bachmann DCC decoders

[Pacific Northern]

I am running DCC, however have not learned how to change CV's or any of the more advanced abilities other than consisting and changing addresses.

However, one of the Model Railroaders I have met has become very experienced at changing CV's.  He asked me if I had changed any of CV's on any of my Bachmann Spectrum DCC steam engines.  I admitted that I had not and he offered to show me which CV's if changed would increase the running abilities of my steam engines.  He explained to me that the factory settings on the Bachmann DCC engines left a lot to be desired as to fine tuning their running capabilities.

I gave him a couple of my engines and he said he would take a look at them and once he had examined the CV settings he would show me which to change and what to change.

Unfortunately for me, I had to leave town for a few days and when i came back he had already returned the engines to my house. So I was unable to learn from him what he had done to the CV's.

One thing I know he did was change the setting for power, the engines now start more quickly and their low speed responses are greatly improved.

I Thought the factory Bachmann DCC engines were very basic and not much could be changed other than addresses. Apparently there are settings on the CV's that will allow one to make changes. and that they are not quite as bare bones as I was led to believe.

[Jim Banner]

While the E-Z Command can change the basic address CV, there are many other CV's beyond this that the E-Z Command cannot change.  It sounds like he changed CV2, the start voltage CV.  It changes how much voltage is applied to the motor when you turn the speed dial from STOP (speed =0) to the first speed step on the dial.  This way you can start the locomotive moving with very little applied throttle.  This can be a bit tricky to set properly because how much voltage the motor it takes to just start motor depends on the load behind the locomotive, the state of lubrication of the motor and gears, the smoothness of the gears, and the ambient temperature, to name a few.  The manufacturer (Bachmann, in this case,) sets CV2 high enough for a reasonably quick start but low enough that there are no jack rabbit starts.  So any particular locomotive can stand some tweeking of CV2.  Note that this applies to standard DCC, not to sound locomotives with Tsunami decoders or with after market decoders with BEMF control.

Jim

[MC]

I have a Bachmann K-4 Dcc that doesn't start until around speed step 14. There isn't any information on the decoder only that it is a 28-step speed control. Can I improve the starting speed by adjusting CV-2?
Thanks,
MC

[Jim Banner]

Most likely, yes.  All of the decoders presently listed in the Products section implement CV2 but because it only a recommended CV, not a mandatory one, it is possible that the earlier decoders did not have it.

Before adjusting CV2, make sure the locomotive is clean and lubricated.  Lack of lubrication and/or hair/lint fouling the axles can slow a locomotive down.  You can adjust CV2 to compensate for this, but then the next time you do clean and lubricate the locomotive, you are likely to find it gives you jack rabbit starts.

Jim