Rob F Posted January 4, 2015 Share Posted January 4, 2015 I got a Heljan class 128 for Christmas and installed a Lenz standard 8 pin decoder via a Bachmann 8 to 21 pin adapter. This works fine, just as expected. However, since it has been on the layout I have on two occasions had two different locos set off on their own when I have accessed the class 128. I moved the 128 to speed step 1 and the other locos just set off at full speed. This is not repeatable or regular, for the vast majority of the time everything works as it should, but twice seems a bit more than a freak occurence, particularly as it has never happened before. My controller is an NCE PowerCab with the new EEPROM installed. the Lenz standard is still at its factory default settings as I have not reprogrammed it at all yet. Any advice or insights would be much appreciated. Rob Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted January 4, 2015 RMweb Gold Share Posted January 4, 2015 I would turn off running on DC on the locos that run away - set CV 29 to 2 (if loco is using 2-digit addressing) or 34 (if the loco has a 4-digit address). Link to post Share on other sites More sharing options...
Rob F Posted January 4, 2015 Author Share Posted January 4, 2015 This may be a bigger problem than I thought. I just had another completely different loco run away and the Heljan 128 wasn't being used at the time. Could this be a fault with the PowerCab as this has never happened before in the 3 years that I have had it? Rob Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted January 4, 2015 RMweb Gold Share Posted January 4, 2015 Have a read of this explanation here - http://tonystrains.com/why-decoders-run-away-or-reset/ I would turn off DC-running on all your DCC locos. Link to post Share on other sites More sharing options...
Rob F Posted January 4, 2015 Author Share Posted January 4, 2015 Have a read of this explanation here - http://tonystrains.com/why-decoders-run-away-or-reset/ I would turn off DC-running on all your DCC locos. Thank you, that is very informative and I will follow that advice. I just wonder why it has suddenly stated to happen. I think this has only occured since the upgraded ROM was installed in the PowerCab but the explanation above seems to be much more about the decoders than the controller. Curious. Rob Link to post Share on other sites More sharing options...
Rob F Posted January 18, 2015 Author Share Posted January 18, 2015 Another update. I have been going through my stock and reprogramming all the decoders to turn analogue operation off and all has been well until today. I put my Hornby class 50 on the layout, which had not yet had analogue operation disabled and is fitted with a Lenz LE1035 decoder. As soon as I set it in motion my Heljan Hymek ran away at full speed. The Hymek HAS had analogue operation disabled. I would be grateful for any further thoughts. Regards Rob Link to post Share on other sites More sharing options...
Combe Martin Posted January 18, 2015 Share Posted January 18, 2015 I had a problem when I put my one and only loco fitted with a Hornby R8249 decoder on the track. About 4 or 5 other locos fitted with other makes of decoder (but not all other locos, over 30 in total) started misbehaving, except in my case they would seem to stop and start randomly at various places on the circuit (My layout is basically a double track circuit, with a lifting section across the door). Each loco so affected stopped or paused at it's own set of places, but each loco had a different set of places. If I lifted the R8249 fitted loco off the track all problems disappeared. Hornby replaced the R8249 and one less (but not all) of the other locos were affected. I solved the problem properly by fitting 'filters' to the ends of each piece of wiring bus. These are described on the Brian Lambert web site, but are a capacitor plus resistor soldered together in series and connected across the ends of the 2 wires of each bit of bus. The above web site quotes the required capacitor and resistor values needed and they're available from Maplins for about £1 per filter. After I did this, all strange problems disappeared. Link to post Share on other sites More sharing options...
Rob F Posted February 7, 2015 Author Share Posted February 7, 2015 Runaways still happening at random intervals, even though DC operation is now turned off on all decoders. I am beginning to think this is a controller issue as it never happened before I installed the PROM update in the PowerCab, or with my previous Lenz Compact controller. Rob Link to post Share on other sites More sharing options...
robertc Posted February 22, 2015 Share Posted February 22, 2015 Rob, given you state this has started to happen over time have a good look at the pickup path on the locos doing this. Clean and lubricate if necessary the pickups as well as a wheel clean. A clean track also helps. Decoders need a regular clean signal or they can do some strange things. regards Bob Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted February 22, 2015 RMweb Gold Share Posted February 22, 2015 I would suggest keeping a log of the ones that run away and see if there's any correlation to the brand of decoder being used. Do you remove capacitors from your locos? This might be a possible problem area. Even locos with their capacitors removed can be affected by a loco in motion that still has them in, as I have found a couple of times. Another area I would investigate is track feeds. Do you have plenty of these? If you don't, then there could be an issue of a weak or corrupted DCC signal in places. You could try doing the "coin test": take all locos off the track and go round the layout placing a coin over the rails and checking that your DCC command station trips out immediately. If it doesn't, it means the track feeds to that area are inadequate, and could be dangerous - a real loco short there could go undetected, causing heat damage to the loco itself (or worse!). Link to post Share on other sites More sharing options...
RMweb Gold RFS Posted February 23, 2015 RMweb Gold Share Posted February 23, 2015 Of course it may still be a command station problem. A few years ago I switched on my Lenz LZV100 one morning and a number of locos shot off at full speed. It was only certain locos but the problem was not intermittent, but thereafter happened every time. It turned out the LZV100 board was faulty and it was replaced under warranty. Link to post Share on other sites More sharing options...
Suzie Posted February 23, 2015 Share Posted February 23, 2015 It could be a faulty Powercab, or even a faulty power supply, but it sounds much more likely to be high impedance in the feeds to the layout. That the Heljan loco is triggering this off is a good sign of this because Heljan locos are notorious for drawing high current. There are a few simple tests you can do to check that things are in order:- First you need to check that the power supply you are using for the Powercab is OK, load it up fully and check that it is still putting out the correct voltage with a digital meter. If you are stuck for a load a 21W car indicator bulb will be about a 2A load. If that is good try the 'coin test' on your layout. Probably best to take all your locos off the layout and try shorting the track in various places to make sure that the Powercab shuts down promptly. If it does not try shorting the output from the Powercab and see if there is a difference - if it then shuts down OK there is a deficiency in the wiring somewhere but if not then there is possibly a problem in the Powercab. Link to post Share on other sites More sharing options...
RhBBob Posted February 23, 2015 Share Posted February 23, 2015 Just a thought ! How many throttles do you have for the Power Cab ? On the GM Prodigy Advance 2, the throttles - I have three - must be separately numbered i.e. 1,2 or 3. Otherwise a loco can receive multiple packets and go on for ever before stopping ! Link to post Share on other sites More sharing options...
Rob F Posted April 11, 2015 Author Share Posted April 11, 2015 All had been well for a while but today got another issue. I had a Bachmann Voyager fitted with a Lenz 1024 and a Hornby class 60 fitted with a Lenz Gold. Whenever I started the class 60 the Voyager would run way at full speed about 2 seconds later. Both have DC operation turned off and have been working fine, as they have both been on the layout together for at least the last week. This was very repeatable and happened at least ten times. No other locos on the layout were affected. I am thinking of putting the old PROM chip back in the PowerCab and seeing if the problems go away as I never experienced the issue before I installed the upgraded chip. ROB Link to post Share on other sites More sharing options...
RMweb Premium ColinK Posted April 11, 2015 RMweb Premium Share Posted April 11, 2015 Hi Rob, I had a similar problem a few years ago when exhibiting my layout, locos just started off at full speed at random and whatever I did, they would not stop. Even taking them off the track and putting them back on the next day, they still went off at full speed. I guessed it was a problem with my ZTC controller, but it was not. I tried a Bachman controller and the problem continued. I got lots of advice from RMweb members, the consesus was that it was caused by something in the school holding the show, possibly 'dirty' mains power. The solution was what people have posted in this thread. I started by resetting each decoder, then switching off the DC capability and that solved it - I've exhibited in the same school several times now using a NCE PowerPro without any problem. Good luck in fixing your problem, it's a real pain. Link to post Share on other sites More sharing options...
Combe Martin Posted April 12, 2015 Share Posted April 12, 2015 All had been well for a while but today got another issue. I had a Bachmann Voyager fitted with a Lenz 1024 and a Hornby class 60 fitted with a Lenz Gold. Whenever I started the class 60 the Voyager would run way at full speed about 2 seconds later. Both have DC operation turned off and have been working fine, as they have both been on the layout together for at least the last week. This was very repeatable and happened at least ten times. No other locos on the layout were affected. I am thinking of putting the old PROM chip back in the PowerCab and seeing if the problems go away as I never experienced the issue before I installed the upgraded chip. ROB Have you tried fitting the filters as I described in post 7 above ? Link to post Share on other sites More sharing options...
RMweb Gold traction Posted April 12, 2015 RMweb Gold Share Posted April 12, 2015 I've had this a few times when using a basic EZ-Command. The two locos that came in the train set worked fine, until I put a Hornby Loco on. I can't remember the decoders but I just went round all the locos and snipped the capacitor out of them. After that no issues, this was at least 5 years ago and things have moved on a lot since then though. You need to start narrowing things down, you've turned off DC so it's not that. Fit the filters as CM as said above, see if that cures the fault. If you still get problems then try putting the old EPROM back in the PowerCab and see what happens. Cheers Ian Link to post Share on other sites More sharing options...
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