Hey guys, I just got a Digitrax Zephyr a few months back and have been changing my locos over to DCC, my problem comes in the fact that now all of a sudden I can't run any non-decoder equipped locos. The headlight comes on full blast but the engine will not move. I checked track voltage on the rails and found it to be 13.8 V's AC! Is this correct? Putting 13.8V's DC in and getting AC out to run a DC loco? And the 13.8V's is on all the time when the track power is on. Also I was expecting to see the voltage to be at zero until the throttle was ramped up. Leaving my meter on I noticed that there was no change in voltage to the track through the throttle. On DCC my locos run great and I have no problems. I contacted Digitrax and they told me about closing switch 39 but that had no affect. Any help would be greatly appreciated.
Thanks,
Chris
I don't have a Digitrax system so I can't tell you where the problem may lie, but with DCC there is always voltage on the track. A DCC system runs a non-decoder equipped locomotive through a trick called bit stretching. The DCC voltage on the track is a high frequency AC square wave. To make a non-decoder equipped loco move, the plus or minus half of the square wave is elongated so the motor receives either plus or minus voltage and thus runs in one or the other direction. It is not a good idea to run a motor for an extended period this way because they can overheat from this continual rapid turning on and off.
The voltage in DC mode is actually Pulsed which looks like an AC signal. I believe they call it signal stretching which is just longer DC pulses.
Chris, are you definitely using a non-decoder equipped loco? Also some older loco's don't like the pulsing DC
Springfield PA
Well that clears up how the heck the engine would work off of the AC! I was beginning to question everything I knew about electric motors! I am sure the latest engine I threw on had no decoder. It was a new Athearn Indiana Habor GP-40 of their RTR collection and I am sure the box did not say DCC ready. Thanks for clearing up the one of the questions!
And just so I've got this clear, I should actually be seeing AC voltage on my track?
Your meter should see the voltage in the AC scale. Basically pulsating DC is AC, just not a sine wave. It also typically fluctuates between zero and a higher DC voltage. It won't usually go below Zero but in reverse I guess it would go between Zero and a negative voltage.
SteelMillTrain44 ...now all of a sudden I can't run any non-decoder equipped locos. The headlight comes on full blast but the engine will not move...
...now all of a sudden I can't run any non-decoder equipped locos. The headlight comes on full blast but the engine will not move...
Are you selecting address '0' when you try to run your non-decoder locomotives? With Digitrax, selecting address '0' is how you tell the system you want to run an analog engine. If you are selecting address '0' and it is still not working, check OpSw 20 and make sure it is set to 't'. That is the default setting, but if it has been set to 'c' it will disable running an analog locomotive.
DCC is not pulsed DC, it is square wave AC, i.e. it does alternate between positive and negative.
SteelMillTrain44 why did you not read the instructions that came with your Zephyr?
I have both the Zephyr and the Zephyr-Xtra and the instructions are clear about running any DC engine.
Also a regular AC/DC volt meter will not read the track voltage correctly. "RRampmeter" from Tony's Train Xchange will get you the meter for the job.
Tony's 1-800-978-3472 or TonysTrains.com
Here's some pics for starters. http://www.tonystrains.com/gallery/rrampmeter/rrampmeteratrest.htm
Wadda ya mean I'm old ? Just because I remember gasoline at 9 cents a gallon and those big coal burning steamers.
It's close enough, especially if you use the Digitrax method and measure between Rail A and ground, and Rail B and ground, and add them together. I really don;t see the need for absolute precise voltage measurements for DCC. Save your money for decoders for the locos that don't have them. A regualr meter will be clsoe enough - you're not goign to be pumping 25 volts into the loco when the meter only reads 13, so there's no fear.
There are two ways to see if the analog is workign properly. WIth no loco on the track, select address 00 and turn the speed to full. The track status LED should go from red-orage to more red, or to sorta greenis, dependng on the direction switch. Flip the direction switch and it should change the other way. Or using the voltage mearueement method I mentioned. CHeck Rail A to ground an Rial B ro ground (ground nt he connector of the Zephyr). If address 00 is set to stop, they should be equal. If you select address 00 and se teh throttle on full, one side will ready higher than the other.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rockislandnut SteelMillTrain44 why did you not read the instructions that came with your Zephyr? I have both the Zephyr and the Zephyr-Xtra and the instructions are clear about running any DC engine. Also a regular AC/DC volt meter will not read the track voltage correctly. "RRampmeter" from Tony's Train Xchange will get you the meter for the job. Tony's 1-800-978-3472 or TonysTrains.com Here's some pics for starters. http://www.tonystrains.com/gallery/rrampmeter/rrampmeteratrest.htm
I did read the instructions, multiple times. It gives very little reference to DC operation and troubleshooting of that system, nor do they give much reference to the actual voltages supplied by the DCS. I have selected the loco at "0" and it didn't move. Track power was on, selector to forward/reverse, voltage verified on the track. My meter is a Fluke 87-5, which I use everyday at work and trust its accuracy with my life and you don't get much better than that. I guess working with a system that I haven't had much time to work on, nor do I have any friends that have model trains. This leaves me to figure things out on my own, or in this case when I don't want the risk of ruining my trains or my controller, I turn to the forum and others who may have had similar experiences. Its one thing to troubleshoot a piece of equipment you or someone you work with have had time with, its another to do it on your own for the first time. I am guessing that I changed some setting now after reading some of the posts and I have to find which one it is.
Thanks, I will go and check OPSW 20 and see what it is set at. I wasn't really worried about the amount of voltage, just that I was seeing AC. I guess I wasn't aware how the whole Digitrax system functioned. The old controller clearly stated DC 0-15v and I was assuming to see the same with the DCS. Guess I need to do more research!
Ok, I went down and tested the same loco and some others and this time it works. OPSW 20 was set at the factory default and I had reset the whole controller once before. This time it works. I did the Digitrax method of A to GND and B to GND and its the same as hooking your meter up to both rails. I was able to see the change in the track status light. I really appreciate everyones help.
By the way, not all loco's like the DC mode of DCC systems. Some will have heat issues. I would use a standard DC controller for DC and leave the DCC system to do what it was made for, DCC.
Just in case you did not see this in the Zephyr guide ( these pages came from "Zephyr-Xtra" but are the same as older Zephyr. )
And in case you hit the wrong button somewhere:
Run a DCC engine and you'll be happier, well maybe.
Good luck.
Edit: Sorry I did not see your post in time that you have it fixed.
Hamitnblue has a good point, so don't depend on the zephyr to check your DC locos even if Digitrax says it's OK. Some of us have learned the hard way in the past.
Hamltnblue By the way, not all loco's like the DC mode of DCC systems. Some will have heat issues. I would use a standard DC controller for DC and leave the DCC system to do what it was made for, DCC.
the heat issues only tend to crop up if you run the loco slowly or slowish? run it up in the higher speeds as if you are running it in, and the heat is less on an issue as the motor isn't fighting itself as much.