I've seen an anomaly I can't explain and have no idea why it's happening. Take a brand new locomotive and it doesn't seem to matter which locomotive or diesel manufacturer it is nor which decoder is in the unit. A locomotive, brand new, out of the box stops running after one hour of operation (more or less at times) stops dead. Not always but most often the lights remain on while the sound dies out. Now I've troubleshot the railroad time and again looking for power drops and I can't detect any. Also, dead spots or shorts....nothing. We are using MRC's, Advanced Prodigy Wireless hand held controller and power supplies. We've tried to reset the decoders back to default or factory settings. Sometimes that works and sometimes it doesn't. When it does work the locomotive will give us a perfect performance and then die again, on line. If it was doing this on the same spot or the same switch I would have some idea what to focus on. It's random. One thing I've noticed the operators doing the programming is doing so on the main while other locomotives are present, usually sitting on a storage track......with the sound on, track being hot. I'm not convinced that's a good idea but it doesn't appear to be a problem. You can call them up and off they go performing all but flawlessly. This phenomena has the owner frustrated and he is about to give up on decoders or better said model railroading all together. Your help to solve this frustrating problem, would be greatly appreciated. Thanks in advance for your help with this matter.
Jim, and of course everyone tuned in here. It doesn't matter what decoder or who manufactured the locomotive or diesel. I believe the owner of the layout has a plethora of decoders all acting the same way. It's possible we are looking at a decoder that is overheating. Why? It was suggested there is an intermittent short on the layout. I've heard the term "Accumulative Short" used at times. I have several ideas as to what might cause it and I will trouble shoot that come Friday. Thank-you, David E., for your phone call. Sorry, I wasn't here to take it. Thanks Jim and David for your come back.
Hey Rick, Saw some post about something close to what you are discribing having to do with multiple throttles. Any chance there is another throttle around there causing it? Jim
Jim, I believe he has two wireless MRC throttles. I'm not sure how that would cause the problem. If one is talking to 201 while the other is talking to 6111 I don't see how you could mix or confuse the two packets of information going out from the power supply. I could see someone hitting a wrong button...finger drag. Shutting the decoder down. That would have to be in the hands of the person's hand control or throttle for that specific locomotive. There are some potential shorts on the layout and I will look at those coming up toward the end of the week. If the owner will allow me to resolve those issues we might see some very real changes in how the decoders respond overall.
It does sound like there are multiple throttles running the same address and it does happen. If someone is running a loco on address, lets say 3, then they stop the loco and remove it from the track without dispatching it. The DCC system thinks the loco is still on the track. Then you come along with another loco that you want to run on address 3 and you aquire the loco on another throttle, your loco will run, but when the command station sends out the update packet to the loco that was previously 3, yours will stop until the command station sends out the update packet to your loco which will restart it. Clearing the memory of the command station, if it is an option, should correct the situation.
Some track problems will be more apparent if you load the track on the opposite side of the suspected problem from the power-feed. I use two 1156 12 volt bulbs in series (~1 to 1.5 amps). If you have an oscilloscope you can also take a look at the DCC waveform under load/no-load conditions and with a loco sitting across any nearby rail-gaps. The track and everything on it make a very complex signal path for the DCC signals. Bob
I will be giving all these considerations some thought. Since the layout I will be troubleshooting isn't mine it will be difficult to move ahead and solve the problem. Thanks RT and retsignalmtr for you advice and come back. Retired signal maintainer. Now that would seem like interesting work.
Hi Rick - A few thoughts based on experience with tracking down hard to find electronic faults. It's really difficult to troubleshoot a complex system all at once, so divide and conquer. If possible, eliminate much of the complexity and test the layout. For example, bring in a separate DCC system like a NCE Power Cab and connect it in place of the owner's DCC system to see if the problem occurs. Shut off everything except the Power Cab, and test the layout. Or using the owner's DCC system, disconnect everything related to wireless operation and operate the layout with a single tethered throttle. The point being: Simplify the control system as much as possible to eliminate some variables. Thoroughly test the simplified layout with a locomotive that has been known to fail in the past. Add back other electronic bits one at a time, testing along the way. You may be able to find a point where the layout starts failing, and you'll have a clue about where the problem lies. Since the problem occurs with multiple locomotives, decoder overheating seems unlikely. On the other hand, something else in the DCC system could be overheating -- command station, booster, throttles. I've heard of cases where just one bad throttle can cause layout-wide problems. Check any equipment with socketed components. Circuit boards or individual ICs that are not fully inserted in their sockets can move just enough due to heating that a pin can work loose. Some circuit boards are notorious for becoming loose in their edge connectors over time, causing intermittent problems. Any batteries in the system should be checked or simply replaced to eliminate them as a cause. With a wireless system, the possibility of RF interference should be considered. Did the start of the problems coincide with installation of any nearly electronic devices that might be emitting RF? This includes non-railroad devices that the homeowner or even a neighbor may have installed. Good luck! - Jeff
Sounds like you need a support group for MRC. https://groups.yahoo.com/neo/groups/MRC-DCC/info Hope this helps. I would throw my two cents in but I am not familiar enough with it to muddy your water.
Jeff, I appreciate your advice here and what you shared affirms we are on the right track. The layout was built with DPDT's installed so we are able to isolate sidings, spurs, and some mainline track sections... in search of any intermittent shorts or those haunting dead spots that might occur because of a loose or oxidized rail joiner, broken wires that arc across or whatever the problem might be. I will share the information you posted here. When Steve and I finally gang up to tackle this problem everything you and others have shared here will be on the table. Train table of course. I have one more nagging question. How do we go about resetting these decoders to factory default. I've asked this same question here before and was given three numbers 3,8,& 9. I can't remember the CV we are supposed to use to re-set the decoder back to factory default? Sorry I lost the sticky note I put this on and can't find it. I realize this is April Fool's but seriously this is no joke and is frustrating the owner of a layout to no end. Well, yes if we can't resolve this operational problem he will destroy the layout. I'd hate to see him do that. Thanks again to everyone for responding here. All suggestions noted and you can rest assured we will be acting on the information shared. Nothing like a little problem resolution to get one's steam up. Can you see and smell the smoke?:wideeyes:
I don't use MRC but based upon your description I would guess its a problem with either the command station or control cab. Reasons being: 1. since it occurs with many different locos it isn't a decoder problem. 2. you state that most of the time when a locomotive stops working the light stays on so that indicates you are still getting power (some power anyway) to the tracks. This means you can rule out a short (unless there's smoke coming from somewhere after the shutdown). I've never heard of a power supply "semi-shutting down" due to an overheat so I'd say you can rule out a funky power supply. 3. The shutdown doesn't occur after a turnout is thrown so again probably not a track short. 4. If you aren't moving the command station and/or power supply around when the shutdown occurs its probably not the wiring connecting the two. Sorry for asking a stupid question but you're not setting anything on top of the tracks (like a tool or hand) that could cause the system to shut down. I've done this before so had to ask. 5. Do you have any auto-reversing units? I've never had one go bad but its a thought.... 6. This leads me to believe its either a problem with the command station or wireless cab. Again I don't know enough about MRC products but are there any status lights on the units that can tell you any more info?? Hope that helps. Brian
CV 8 set to a value of 008 usually works for me when I ever have to reset a decoder to factory defaults. It will set the address of the loco back to 3 and you may have to reset CV's 2,3,4,5 and 6 along with the sound levels if applicable.
The factory reset procedure differs between brands of decoders. They are NOT all the same. Here is a PDF document from NMRA that might be helpful: http://www.nmra.org/sites/default/files/sr201402_dcc.pdf - Jeff
John, Thanks for the heads up. We'd like to think we have it figured out. Thinking the DCC packets of information aren't getting to the locomotive and it's shutting down as a result. I've looked at "Accumulative shorts" as a possibility. I'm not sure who coined such. Willing to say it's possible that a number of short's on a layout, not strong enough to shut it down may act on the decoder in such a way as to cause it to overheat. However, each time I look at that I have trouble understanding how a short could cause something to overheat....enough to shut down the decoder. Thinking instead the packets of information are being lost the result of intermittent short's, most likely in the switch mechanisms and is disrupting the signal causing the diseasel or locomotive to shut down, as a result. To all, don't doubt that we won't be looking at everything submitted here. Thanks again for the help.
An intermittent short or soft short if you will, could cause a current draw that boarders on the decoders limits. My groups problems mostly ended up being around poor connections or substandard wiring not evident until there was action in that section. You could also have a simple dispatch issue. If a throttle is left active with a zero speed setting by being plugged in or with a battery if wireless, and a loco address is active on it, does the command station send out the "0" throttle setting every so often. Digitrax does this every minute and is the root of much frustration in consists. This, from a torn Digitrax at the club and NCE at home user.
Well, I don't think we've solved the problem. I still need a back door access to the decoders in order to reset them back to factory defult. The front door isn't working. You might want to check out my thoughts on DCC Friendly switches, BarstowRick.com: http://www.barstowrick.com/dcc-friendly-switches-turnouts/ Oh, before I forget it's not an easy read despite my best efforts. I will revise my comments if needs be. Or add your comments if you will so allow me to. Thanks for your help.
Not sure what you mean by back door access. That would be the programming track. I regularly use prodigy wireless at my club. I've never had this kind of problem. Or rather, never so consistently. My first question is, how many throttles are active in the main and my second is how many locos on powered tracks. Also, is the layout divided into power districts?
How good are the power supplies? We have found many bad brick power supplies so spend a little extra for something with cooling fans and more amperage.
I concur with Jeff's advice. Proper troubleshooting requires isolating specific possible failures one by one. There are several approaches to this, but here is one I would try. First, remove all locos from the layout except one that has been known to fail. See if the failure recurs. If not, then I suspect that what is happening is that the Prodigy command station is somehow getting "overloaded" in trying to keep track of all the locomotives or overloaded by the power draw from many locos. (My first suspect would be the power supply - as John notes, cheap power supplies create all kinds of problems). If this fixes the problem, then you add back locomotives one by one until the problem recurs. Now, you're not done. If the problem comes back, remove the last loco before the problem popped up again, and try a different one. It is also remotely possible that there is a single locomotive on the track whose decoder is causing the command station to go wacky. If replacing the last loco with a different one doesn't cure the problem, then I suspect some sort of "load" issue - too many locos, bad power supply, etc. If replacing the last one does cure the problem, then there may be a bad decoder in that unit causing issues. Suppose, however, that going to one loco on the layout does nothing - the problem persists. Start disconnecting individual pieces of the Prodigy system and test. First, remove throttles one-by-one. Then remove accessories like a radio control interface, until you are down to where Jeff talked about: only the command station and one throttle. Still having problems? Start disconnecting sections of the layout if you can (e.g., if the layout has "power districts," disconnect them one-by-one). If you can't do this, then when you get down to just the command station and one throttle, you'll have to borrow a different digital system, hook it up (again, just the command station/one booster and a single throttle) and see what happens. If you do this systematically, at some point you will find the failure. But it's going to take a while and a LOT of patience. John C.
