Aussie Fred Posted August 8 Share Posted August 8 Further to add to my woes with this loco, it is now experiencing runaways - at the same spot on the track, a bend, the sound stops and the loco hurtles away at top speed until I hit the emergency STOP button. Only started doing it this morning and only happens at random. It can run for half a dozen or a dozen ciruits and then WHAM. The further woe on this loco is that although it worked perfectly when I first bought it (ran on dirty track), it now does not produce any steam. I am losing patience with this "steam" feature on Hornby locos. Link to comment Share on other sites More sharing options...
96RAF Posted August 8 Share Posted August 8 Check CV29 isn't set for DC running and check CV2 (kick start) hasn't corrupted to a high value. Do you have a bus terminator (snubber) installed. Link to comment Share on other sites More sharing options...
Aussie Fred Posted August 8 Author Share Posted August 8 Went through CV29 and parameter was DCC only. No, I do not have a bus terminator installed it has been sugessted on my size layout not needed. What is correct value for CV2? Link to comment Share on other sites More sharing options...
96RAF Posted August 8 Share Posted August 8 2 hours ago, Aussie Fred said: What is correct value for CV2? 0 or if you have a sticky motor 1 or 2. The benefits of a snubber can be gleaned on any size layout. Link to comment Share on other sites More sharing options...
Fishmanoz Posted August 8 Share Posted August 8 The symptoms certainly point to DC Runaway but that shouldn’t be possible with DC Running disabled in CV29. Irrespective, it seems you may have connection issues at that particular point in the track and, if not the track itself, is the loco lifting and losing contact sometimes at that point. Snubbers are used to suppress transient spikes arising when connection is lost momentarily. They arise due to stray capacitance and inductance in the overall power circuit including the track, its connections and the bus. Certainly the bigger the layout the more significant the strays but the history on this site shows significant improvements on average size layouts. And Murphy will confirm that, if a spike is to take out any electronics connected, it will be the most expensive item. Link to comment Share on other sites More sharing options...
Aussie Fred Posted August 9 Author Share Posted August 9 I have the snubbers so will fit them when it gets warm enough to go under the layout and do it. Link to comment Share on other sites More sharing options...
Paul-380474 Posted August 9 Share Posted August 9 (edited) Never heard of 'snubbers' before. Sounds like a good idea. I have a circular (well, a folded figure of 8 one half on top of the other and connected by spiral tunnels) circuit. Where would I place a pair of snubbers? Edited August 9 by Paul-380474 Link to comment Share on other sites More sharing options...
96RAF Posted August 9 Share Posted August 9 27 minutes ago, Paul-380474 said: Never heard of 'snubbers' before. Sounds like a good idea. I have a circular (well, a folded figure of 8 one half on top of the other and connected by spiral tunnels) circuit. Where would I place a pair of snubbers? You connect a snubber across the open end of your bus. If the bus is fed from one end, the snubber connects across the other end. If the bus is a T with the controller in the middle you fit one at each open end. If the bus is radial or star connected then you can fit one at every open end. Link to comment Share on other sites More sharing options...
Rog RJ Posted August 9 Share Posted August 9 For a circular (loop) layout a snubbed can be fitted anywhere convenient. Link to comment Share on other sites More sharing options...
Paul-380474 Posted August 9 Share Posted August 9 They come in pairs so I just fit each one well away from each other and the elite controller? Link to comment Share on other sites More sharing options...
LTSR_NSE Posted August 9 Share Posted August 9 @Paul-380474 do you just connect your elite to the track in one place? Or multiple places? Or do you use an electrical bus (i.e. separate cable that runs length of track & has multiple connections to track from it.) Link to comment Share on other sites More sharing options...
96RAF Posted August 9 Share Posted August 9 2 hours ago, Paul-380474 said: They come in pairs so I just fit each one well away from each other and the elite controller? Go and read my earlier post. Link to comment Share on other sites More sharing options...
ColinB Posted August 9 Share Posted August 9 I really do doubt that a snubber is going to fix your DC runaway. Generally when my locos do it, it is because of dirty track. The software in the decoder gets confused with the intermittent signal. It also depends a lot on the software inside the decoder and how it copes with a disappearing DCC signal. A did a load of tests with different decoders, some were terrible some were brilliant. So coming back to the subject it could be that horrible connector or it could be that some of the pickups are not working properly. What I do is lift the tender off the track and see if the loco works and then put the tender back on the track and lift the loco. You would be amazed how often I find one of pickup sets is not working. Of course then there is the track. 1 Link to comment Share on other sites More sharing options...
ntpntpntp Posted August 9 Share Posted August 9 I tend to agree with @ColinB in my experience some brands of decoder get "locked" into DC mode if they lose the DCC signal due to momentary power loss over dirty or uneven track, dead frog points etc. I have an old (20 years) NCE large scale decoder in one of my garden locos which had a habit of doing it until I disabled DC. 2 Link to comment Share on other sites More sharing options...
Fishmanoz Posted August 9 Share Posted August 9 Hadn’t occurred to me the runaway and the snubbers were the same issue, see my earlier post. However, if the runaway is due to losing contact briefly for whatever reason, a snubber (they don’t have to come in pairs) may avoid subsequent damage. Link to comment Share on other sites More sharing options...
Aussie Fred Posted August 10 Author Share Posted August 10 (edited) Don't have to worry about runaway now. The POW has decided not to move at all, sound OK flickering firebox OK, just won't move on mainline or test track. Edited August 10 by Aussie Fred Link to comment Share on other sites More sharing options...
Paul-380474 Posted August 10 Share Posted August 10 16 hours ago, LTSR_NSE said: @Paul-380474 do you just connect your elite to the track in one place? Or multiple places? Or do you use an electrical bus (i.e. separate cable that runs length of track & has multiple connections to track from it.) Multiple places. Cable runs to all parts of the track and connects all over the place. Link to comment Share on other sites More sharing options...
Paul-380474 Posted August 10 Share Posted August 10 14 hours ago, 96RAF said: Go and read my earlier post. Read it. Potentially several snubbers then. Link to comment Share on other sites More sharing options...
Fishmanoz Posted August 10 Share Posted August 10 On each significant open end or once to a loop. Link to comment Share on other sites More sharing options...
Fishmanoz Posted August 10 Share Posted August 10 2 hours ago, Aussie Fred said: Don't have to worry about runaway now. The POW has decided not to move at all, sound OK flickering firebox OK, just won't move on mainline or test track. Start with Standard HM7000 troubleshooting (unlink/delete/turn off/restart etc) and the chances are that will get things going again. 1 Link to comment Share on other sites More sharing options...
Aussie Fred Posted August 10 Author Share Posted August 10 I am at present using a elite controller. I haven't taken the plunge to HM7000 on my tablet yet, but looks like I have to get into the right frame of mind and give it a try. Link to comment Share on other sites More sharing options...
ColinB Posted August 10 Share Posted August 10 The HM7000 is usually pretty reliable so I really do doubt it is that. The firebox flicker is working so the loco is picking up power. Does the sound work? If it does then the tender is picking up power, if it doesn't then it is the HM7000. If the sound is working it then comes down to one thing, the dreaded drawbar connector. Now what you can do if it is that, is disconnect loco and tender and reconnect them, that might be enough to scape off any oxide on the connector. If not you might have to lightly clean the contacts on the drawbar connector. Normally it would be a return to Hornby but you are in Australia, so very carefully use a track rubber or ink rubber to clean the connector. You need to remove any oxide which is why you use a rubber, just iso probably won't do it properly. Once it is clean then finish up with the iso to remove the residue. If none of this works, sadly it is a return to Hornby. Link to comment Share on other sites More sharing options...
LTSR_NSE Posted August 10 Share Posted August 10 (edited) @Aussie Fred currently the most common cause (with HM7k decoders) of sound & lights working, but no movement is a corrupted CV19 value*. Try a CV19 reset or else a full CV reset (write 8 to CV8). If neither of these are to blame then the other troubleshooting tips from Fishy & Colin will be necessary. *(Hornby are working to prevent this corruption occurring.) Edited August 10 by LTSR_NSE Link to comment Share on other sites More sharing options...
Aussie Fred Posted August 10 Author Share Posted August 10 I did the CV29 check and ended to CV0004 R and got CV004 R XXX which means it could not be read. It is late night here, so I will have a look at CV19 reset and worst case a full CV rest if needed in the morning. Thanks all for you help so far. 1 Link to comment Share on other sites More sharing options...
96RAF Posted August 10 Share Posted August 10 CV4 is decelleration. Link to comment Share on other sites More sharing options...
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