rorz101uk Posted February 20 Share Posted February 20 Good evening I have fitted both my J72 with an gaugemaster next18 decoder and a KungFu stay alive, as you can see in the video at soon as the power has been turned off the loco goes the opposite direction, is there anything to do with the DCC chip? CV maybe? Help and advice will be appreciated 👍🏻 Link to post Share on other sites More sharing options...
RMweb Gold bandmbill Posted February 20 RMweb Gold Share Posted February 20 How have you connected the stay-alive? My guess is that the stay-alive is connected to the track input of the decoder not to the positive and ground - it charges up and when track power is removed the stay-alive is seen as a DC supply…… Link to post Share on other sites More sharing options...
rorz101uk Posted February 20 Author Share Posted February 20 43 minutes ago, bandmbill said: How have you connected the stay-alive? My guess is that the stay-alive is connected to the track input of the decoder not to the positive and ground - it charges up and when track power is removed the stay-alive is seen as a DC supply…… On the circuit board there are tabs that are for stay alive on the J72 and I have soldered them on, I’ve followed Hornby mags instructions Link to post Share on other sites More sharing options...
woodenhead Posted February 20 Share Posted February 20 Probably worth a photo of the circuit board, the wires and the Stay Alive - a picture tells a thousand words. Link to post Share on other sites More sharing options...
rorz101uk Posted February 20 Author Share Posted February 20 I have done exactly what the photo and instructions Link to post Share on other sites More sharing options...
RMweb Premium peterm1 Posted February 20 RMweb Premium Share Posted February 20 It's a weird one, but clutching at straws; is DC running disabled? Link to post Share on other sites More sharing options...
Nigelcliffe Posted February 21 Share Posted February 21 (edited) 9 hours ago, rorz101uk said: Good evening I have fitted both my J72 with an gaugemaster next18 decoder and a KungFu stay alive, as you can see in the video at soon as the power has been turned off the loco goes the opposite direction, is there anything to do with the DCC chip? CV maybe? Help and advice will be appreciated 👍🏻 Most likely explanation is DC-running is enabled in the decoder (CV29). The decoder interprets this as DC, so engages full power in the DC direction. Turn off DC running to deal with the problem. https://www.2mm.org.uk/articles/cv29 calculator.htm Edited February 21 by Nigelcliffe Link to post Share on other sites More sharing options...
rorz101uk Posted February 21 Author Share Posted February 21 4 hours ago, Nigelcliffe said: Most likely explanation is DC-running is enabled in the decoder (CV29). The decoder interprets this as DC, so engages full power in the DC direction. Turn off DC running to deal with the problem. https://www.2mm.org.uk/articles/cv29 calculator.htm Thanks for this, does the stay alive still work? Link to post Share on other sites More sharing options...
ColinB Posted February 21 Share Posted February 21 Do you have another make of decoder you could try with it, it may well be the decoder. I use exactly those "stay alives" in my locos but mine are 6 pin Zimo with the stay alive attached to pads on the decoder PCB. My locos definitely run on when I turn off the power which is what it is meant to do, but in the right direction. I found out recently there is a CV on a lot of decoders that sets the "time allowed for missing signal", so check the CVs on your device. I am wondering if as it powers down it confuses the last DCC signal as "switch direction" then the "stay alive" does the rest. It might be DC run away though, I have found some decoders are prone to it more than others. I recently bought a different sound decoder ( I normally buy Zimo or Hornby) and was horrified when the loco went shooting backwards when it lost the DCC signal. I have never seen Zimo, LokSound or Hornby do that. Link to post Share on other sites More sharing options...
rorz101uk Posted February 21 Author Share Posted February 21 4 hours ago, ColinB said: Do you have another make of decoder you could try with it, it may well be the decoder. I use exactly those "stay alives" in my locos but mine are 6 pin Zimo with the stay alive attached to pads on the decoder PCB. My locos definitely run on when I turn off the power which is what it is meant to do, but in the right direction. I found out recently there is a CV on a lot of decoders that sets the "time allowed for missing signal", so check the CVs on your device. I am wondering if as it powers down it confuses the last DCC signal as "switch direction" then the "stay alive" does the rest. It might be DC run away though, I have found some decoders are prone to it more than others. I recently bought a different sound decoder ( I normally buy Zimo or Hornby) and was horrified when the loco went shooting backwards when it lost the DCC signal. I have never seen Zimo, LokSound or Hornby do that. eventually I’m planning to get a loksound next18, for both locos but recently I’ve been looking at locos just because if you don’t get them now, there may never have another batch 👍🏻 Link to post Share on other sites More sharing options...
RMweb Premium peterm1 Posted February 21 RMweb Premium Share Posted February 21 How did you go with the answers from me and Nigel Cliffe? Link to post Share on other sites More sharing options...
rorz101uk Posted February 22 Author Share Posted February 22 10 hours ago, peterm1 said: How did you go with the answers from me and Nigel Cliffe? Yep it all worked but does the stay alive still work though? Link to post Share on other sites More sharing options...
Nigelcliffe Posted February 22 Share Posted February 22 9 hours ago, rorz101uk said: Yep it all worked but does the stay alive still work though? If you tried it, then you'd know whether the stay alive still works. Link to post Share on other sites More sharing options...
rorz101uk Posted February 22 Author Share Posted February 22 2 hours ago, Nigelcliffe said: If you tried it, then you'd know whether the stay alive still works. Well, as soon at the power is removed it stops, so it must be the way the circuit board has been design? Link to post Share on other sites More sharing options...
Nigelcliffe Posted February 22 Share Posted February 22 49 minutes ago, rorz101uk said: Well, as soon at the power is removed it stops, so it must be the way the circuit board has been design? No, its how the decoder is working (or not working). I don't know where Gaugemaster sourced their next18 decoders, but a quick look at their manual suggests its not a very advanced design. Different decoder and it will work - a J72 I did a couple of years ago would run for at least 2 feet without power. I used a Zimo decoder, which is what I guess was used in the Hornby magazine article. 1 Link to post Share on other sites More sharing options...
rorz101uk Posted February 23 Author Share Posted February 23 7 hours ago, Nigelcliffe said: No, its how the decoder is working (or not working). I don't know where Gaugemaster sourced their next18 decoders, but a quick look at their manual suggests its not a very advanced design. Different decoder and it will work - a J72 I did a couple of years ago would run for at least 2 feet without power. I used a Zimo decoder, which is what I guess was used in the Hornby magazine article. Right O, I’m planning in the future to get an ESU Loksound next18 to fit, Link to post Share on other sites More sharing options...
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