I am using digitrax and have decoders installed in 6 locomotives at this time. They all run very nicely, but two of the six have a strange issue. If for any reason track power is removed from them (say some loco runs through a switch that is set against it, or when I first power up the system) these two do not respond to commands. If I tap them or spin them on the turn table they will always ‘wake up’ sooner or later. The other loco’s all ‘wake up’ the instant that power is restored. I want to make sure that I am clear - the cause of the loss of power need not involve this loco - it will still have this problem. Also, no physical change has happened to this loco to cause the problem - yet a physical change (I tap it) seems to be the solution. I’ll also mention that these loco’s have been running fine (except for this issue) for several months. Digitrax does not seem to have any idea. I have switched out decoders (several of them) and completely re-wired - no change. Both of these loco’s previously had Keller On-board throttles in them (that I had installed, so I’m some what familiar with command control stuff) and worked fine.
I would like to say that Digitrax has been very nice to work with and that I am very fond of their system and would recomend it to anyone. I do not think this is a digitrax issue.
Any ideas?
Depending on how u installed it…There is one thing no one has mentioned.And being in electronics the first thing i look for is a COLD sodler joint.Means solder didnt take right and there is no contact(incase u didnt know) try that too.
There can be several possibilities here. Let’s assume you have installed the decoders correctly. There could be dirty track and/or dirty wheel sets. It sounds like you are having a power loss somewhere. Check and see if you power supply is strong enough, and not dropping voltage. You can use the “quarter test” in the Digitrax manual. If we eliminate everything but the engine, then trace the power transmission from start to finish. Make sure the wheels sets are clean. Make sure the bronze wipers that ride on the truck contacts and making good contact, and are also clean. Bend them down to increase the tension and improve contact. If you are pulling decoder power from the light board, make sure the light board is making good contact with the frame. I’ve had Kato’s where the light board did not make good contact with the frame where they slid in. This fixed a lot of problems like you described. Let us know what you find out.
Pete:
Could you tell us what kind of locomotive and what the decoder is? Is it a plug in decoder or a hardwire. If its a plug in decoder, it could be a problem with the socket in the locomotive.
Will await your reply for further troubleshooting help.
Mike Tyl
Green Diamond Hobbies
I’ll grant you that a cold sodler joint is a possiblity, but I can not see how that would cause the exact symptoms that I am getting. Remember, there is no physical impact at all on the problem locos to make them stop running. So that would mean that a cold joint was working and now does not - and that it does this in exactly the same mannor every single time.
It would seem to me that a cold joint would behave like a loose wire. This is not like a loose wire.
I will however see if I can find someone with a resistance solder system to see if they can give my tender pickup lead a zap. That is the joint that I had the most difficulty with on all the loco’s.
Thanks, Pete
I am an HOn3 modeler of the EBT. All the loco’s are Brass Hallmark 2-8-2’s. The decoders are digitrax (sorry, I’m at work and can not look up the code - they are all the same as the one that came with my empire builder). This means that I had to solder the wire connections to the loco/tender leads, but that at the decoder I am using the digitrax harness.
I have switched out the wire/harness - no change.
I have switched out the decoder - no change.
I have re-soldered all the wire joints to the loco/tender - no change
I have drilled a hole in the tender floor and put the pickup wire in it - then soldered - to try to ensure a good joint (the tender pick up is the hardest joint to solder) - this also made no change.
Thanks for your help, Pete
Thanks for your help.
Decoders must be installed correctly as loco works.
I clean track regularly and problem is not location based
the issue must be in the engine/decoder. Do I understand you to say that you have seen examples of a loco that works fine but fails to ‘wake up’ after power is removed? And that this was related to power pickup?
It just seems so odd that an incident that involves no physical change can cause a working loco to stop working yet once working that it will continue to work untill power is removed. I’d think that if it was a power pickup issue that the loco would sometimes twist on the track or hop a bit going over a turn out and that this would break the connection - but that never happens. The only way it stops working is if some one forgets an runs into a turnout that is set against them (it is usually someone else’s loco as I am the only one who runs the ‘sick’ ones at this time). This will cause digitrax to shut down until the short is fixed. At that time all the other locos pick right back up, but these two are not responsive.
Thanks for your time, Pete
First off, you’ve gotta figure out if it’s the loco or the decoder. Easiest way to do that is to swap decoders with another loco. If it happens in the “new” loco, then it’s the decoder’s fault. If not, it’s the loco.
The other thing no one’s mentioned – and this is a longshot – is that there’s a cold solder joint inside the decoder. Again, you’ll be able to tell if it’s the decoder by doing the test above.
-Gerry
Pete:
You said you changed out the decoder with no change. Does this mean the new decoder acted the same way. If so, you have a short somewhere in your locomotive wiring. It could be that a wire is pinched enough somewhere that is barely shorts out. I would ask Digitrax customer service to send you a dummy plug. Pull the decoder off the harness and place the dummy plug on it and try to run it on regular DC or as address 00. See if it acts up. If so, it would be a problem with the way the harness is wired in the locomotive. How old are these engines? Just another thought. It could be an older motor that has brushes that are cogging very roughly as it attempts to rotate. I newer Digitrax decoder with speed stabilization might help with that problem. You might also want to try a Lenz 130XF decoder with back-emf to see if that helps as well.
Mike
Green Diamond Hobbbies
DCC Dealer and Installer
greendiamond@msn.com