Roundhouse 4-4-0 w/ MRC decoder and a headlight issue

[sparkyjay31]

Any idea why the headlight goes on at even speed steps and goes off again at the odd speed steps? Is this a CV that can be adjusted? Please don't tell me "you should have known better than to get a MRC decoder" or anything like that. I'm not looking to start a fight. I just want to know if it's a CV that I don't know about. Thanks, Jay

[Hamltnblue]

I would try resetting the decoder.  Then make sure it's set to 28 speed steps.

Also try changing the speed step setting on the throttle from 28 to 128 etc.

 

[rrinker]

 That's exactly the problem, you're on the wrong speed step setting. The decoder is set for 14 and you are sending 28/128. In 14 SS mode, the lowest bit of the speed value is the headlight on/off control. So it's a 1 on odd numbers and 0 on even numbers. Result, as you advance one speed step at a time, the light will be on, then off, then on. Check the value you have in CV29.

                                     --Randy

 

[richhotrain]

The value of CV 29 has to be reset on the decoder to change the speed steps from 14 to 28 (or 128).  Somehow, the decoder got set to 14 steps which will make the headlight toggle on and off with each speed step change.

If you are unfamiliar with CV 29 which performs a number of functions, check the owner's manual that came with the decoder.

Rich

[richhotrain]

Oops, Randy, you beat me to it.

[sparkyjay31]

Thanks guys for the help. I'll give it a go first thing in the AM.