If you dive into the NMRA standards and rp's for DCC you'll see that 14 and 28 speed steps use the same packet format except that since you don;t need as many bits to indicate 14 posisble speeds, they used one to also indicate the F0 status. The LOW bit (I don;t even want to know what they were thinking). So, for ever odd number, the bit is on, for every even number, the bit is on. 0 off, 1, on, 2 off, 3, on, etc. So if CV29 is programmed for 14 speeds steps and you send 28, the loco speeds up and slows down just fine, but every time you're on an odd speed step, the lights will be on, and on an even speed step, they will be off. That's why there's a setting in CV29 for it - bascially it's tellign the decoder to use that extra bit to double the speed steps or to use it for the headlight status.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
First time I've heard of the 14 speed step issue flickering lights. Always good to learn something each day.
Springfield PA
I can't believe I didn't see this before, but I went back to the box the engine came in and found a spec sheet under the foam insert, stuck to the underside. It is an Arnold DCC decoder and was set for 08 address because the road number is 4008! It also gave the CV values and what they controlled. Wish I had checked the box thoroughly the first time.
Bob
Life is what happens while you are making other plans!
Well, it was the speed step and I had to set it to 14, but it doesn't seem to respond as well now. I will most likely replace the decoder at some time in the future (too many other fires to put out!), but at least the light stays on steadily.
As far as the mfg of the decoder, I looked it over and don't see any markings.
Thanks to all of you
farrellaa I checked all the solder connections and the tender light is connected with a new 2 pin micro connector.
I checked all the solder connections and the tender light is connected with a new 2 pin micro connector.
You said you weren't sure who made the decoder....If you opened up the tender and checked the connections, you must have been able to look at the decoder. It should be labelled with the makers name like "TCS" or whatever??
After your clarification, I agree with Randy and Robert about the 14 speed step setting being wrong. Please check CV29 to see if you are running 28 speed steps. And make sure your throttle is set to the same 128/28.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Well, if it goes on and off with each speed step, then it is the 14 vs 28 speed step issue. Put 2 (no DC operation) or 6 (DC operation allowed) in CV29 and see if that works. If it's an old decoder it may not be able to do 28/128 speed steps, if it can't, see the section in the Zephyr manual about Status Editing. Or consider replacing it with a newer decoder than can do 28/128 for smoother control. Try CV29 first though.
I need to clarify a few things that may not have been written clearly in my post. I am running Digitrax Zephyr DCC and the decoder is the factory installed one from Rivarossi, which is dual mode DC/DCC. The literature from Rivarossi stated that it was set for address 08 as the default, which I have not changed. I did not buy this engine new, but used on Ebay, but it is in excellent condition and ran flawlessly on DC, before I went to DCC. Still does except for the rear light which I just installed.
I watched the engine today with a better understanding of what may be going on and how to describe it. The back up light comes on when put in reverse and as the speed is increased the light goes off and on with each 'step' or 'degree' of movement of the throttle knob. It appears to flicker if I advance the throttle steadily, that is it goes off, on, off, with each movement or degree of rotation of the knob. If I stop at any point, it may be on or off, but it is not flickering, just steady on or off. When I move the throttle again, the light comes on or goes off, depending on where it was at rest. I can run the loco at any steady speed and have the light on, as long as I gave the knob a slight movement after the original stop point. I hope this makes more sense and I apologize if I have confused or mislead anyone. I certainly would like to resolve this but not knowing what decoder it is and what the CV's control, I can only guess which ones to change. I will try to check CV29 with the Digitrax manual and see if I can change the speed steps. After watchiing the engine today, that is what it looks like is going on. I am relatively new at DCC and have some issues getting the programming to work.
I appreciate all your comments, suggestions and even just observations. If I didn't have you guys on this forum, I probably would not have gone to DCC. Please keep the suggestions or questions coming until we figure this out.
Thanks again,
I think he descirbed his situation a little better in his last post: "...When I said that it flickers, I meant that it goes off and on as I change speed and it will go off and stay off until I move the throttle knob..." - still sounds like the 14 vs. 28 speed step issue to me.
14 vs 28 speed steps results in the light alternating on and off with each speed step increase. This is NOT what is happening.
I stand by my statement. The decoder is probably programmed to dim the light, doesn;t matter if that's what you WANT, that's what it's trying to do. And doesn;t work very well with LEDs. Best thing would be to reset the decoder completely, if you knwo what kind it is and there is a reset option. Not all decoders reset the same way. Default though shoudl be the headlight on in forward, adn the backup light off, and the backup light on in reverse and the headlight off, no dimming, no special effects. Simple on and off should work fine, it's dimming that some decoders have problems with LEDs. In fact with out of the box settig son TCS decoders, if I set the 'dimmed brightness' low enough, they flicker too.
Things may have changed at Rivarossi/Hormby since the three years in which I have had my C&O H-8, but that engine came either DC or DCC with sound. The sound decoder used at the time was a LokSound 3.5
Crandell.
Robert
While I agree with you on the techinical aspect of 14 speed steps, I don't think that is his problem. As he stated, it flickers at low speed, then becomes steady as the speed increases.
He's also hinting that he's running it on a DC layout.
He needs a resistor and a constant lighting circuit (Diode) bridge. with a 3.3V LED lamp, not a 12V like he's using.
RR never put regular DCC decoders in their engines. They were just DCC ready. This sounds like a post install job. They did however put a few LokSound decoders in their bigger units.
If you put the unit on the programming track, it should give you a Mfg ID and product #. If you can give us that number we can tell you who made your decoder and the possible model.
BTW: RR is still around, manufactured by Hornby now.
I'll say it again, It sounds like the decoder is set for 14 speed steps and you are sending it 28 speed step commands.
CV 29 sets the speed steps in the decoder. Look up "Status Editing" in the Zephyr manual to see how to change the speed steps you are sending the decoder. If the decoder supports 128 speed steps, you should be able to use 128 speed steps on the Zephyr, regardless of the decoder setting. If you have to use 14 or 28 speed steps, then the Zephyr setting for that loco's address has to match the setting in that loco.
The 14 speed step command uses a bit for the headlight. The 28 step command uses that bit to double the number of speed steps and sends the headlight command in a seperate command. If the decoder is expecting 14 speed step commands and you send it 28 speed step commands, the decoder reads half of the speed step as "light on" and the other half as "light off".
Are you running DC mode?
A 12V light will not light if you are only putting 6 Volts to the track.
It's also possible your wheels or track are dirty.
Randy,
I think you misread my question, I don't have a sound decoder and I don't want the light to dim, just stay on. When I said that it flickers, I meant that it goes off and on as I change speed and it will go off and stay off until I move the throttle knob. To make it stay on I have to move the throttle knob just a little in the opposite direction; if I am slowing down I have to move the knob 'faster' just a little and it will stay on as long as I don't change speed again. I am going to try to reset the decoder today and see if that helps.
Thanks,
Well if it doesn't have sound then it's not a sound decoder, and since SOundtraxx just came out with their non sound decoders, it's probably not one of those, either. So I'll go with my other option, that it's set to be dim when stopped, and the PWM is too slow a frequency and is visible. LEDs don;t really dim, the best you cna really do it turn them on and off really fast and vary the on time vs the off time to make it look dim. Some decoders like NCE and TCS handle this very well, TCS I think is even better because they have a whole bunch of settings to actually customize this sort of thing. Others work best with incandescent lights and not LEDs, like Digitrax. If this was a regular bulb and not an LED it would probably be fine.
I don't know who makes the decoder,it is the one from Rivarossi and it doesn't have sound. This is one of the later runs with small flanges and can motor. I have no literature or way of knowing what CV settings they use. I could try CV8 and set for 8, but don't know what that would do. Does anyone know how to get this info since Rivarossi is out of business? I am guessing this one is from the early 1990's.
The comment about 14 vs 28 speed steps makes sense, but the engine runs from a very slow creep to full speed (although not as fast as it was on DC.).
As for being a Soundtraxx decoder, did Rivarossi use them? I thought it might have been a Marklin or other european brand. It doesn't have any marking on it.
Thanks for the comments and suggestions. I will try to reseaarch this a little more to find out about the decoder. Worst case I can put an NCE or Digitrax in.
Soundtraxx decoder? That's a known problemin those, that LEDs on the rear light output flicker. If it's only when stopped and not at any other speed, it could just be programmed for some special effect - or dim while stopped, and the 'speed' of the PWM function output (which is how they control dimmign and special effects) is too slow and allowign the LED to completely go out instead of blinkign it on and off a a rate too fast for your eyes to follow which results in the LED appearing to be dim instead of brightly lit. Some decoders have configuration settings for thisTCS for one has tons of parmeters to configure the function outputs - but you need their comprehensive manual from their site, not a peep is made about this capability on the simple programmign pamphlet that comes with the decoders.
You could also do a reset of the decoder to see if it fixes your issue.
It sounds like the decoder is set for 14 speed steps and you are sending it 28 speed step commands.
I just installed a rear backup light in my HO Rivarossi Big Boy and it is working eratically. I used a 12v LED and wired it into the decoder; blue for common and white for power from reverse signal. It works until I move the throttle and will go off or flicker on and off until I move the throttle just a hair in the opposite direction from where it was (I am talking about the throttle knob, not the loco direction).. Once I move it slightly, it stays lit. I am using a Digitrax Zephyr and the Big Boy is running on the factory decoder on address 08 (defaut from factory for Rivarossi). The engine runs fine otherwise. I just can't figure what would cause this. I checked all the solder connections and the tender light is connected with a new 2 pin micro connector. I checked the connector and it is tight. It almost acts like the throttle knob is affecting the power to the rear light. Any suggestions?