Leebo Posted November 7, 2020 Share Posted November 7, 2020 Morning folks,Newbie to the site and after a bit of help. I've been into trains since I got my first set when I was 10 but only now building a layout (now 37).I'm only used to the very basics with little electrical knowledge but I've decided to jump into DCC. I'm pretty handy so can do some simple soldering etc but having just converted my old Intercity 125 HST (Class 43) following Brian Rootham's excellent guide, I'm struggling to get the loco going both forward and back. When I run the loco "forward" it runs a treat, however if I change the direction on my controller (Hornby E-Link) I get an error in RailMaster to say there's possibly a short. I've checked all the wiring but nothing seems wrong, from what I can see it all looks setup ok but the damn thing won't go in reverse.I've tried on a single piece of track and an oval loop with the same results on both.I hope this is enough info but if there's anything I've missed just let me know :)ThanksLeebo Link to comment Share on other sites More sharing options...
Leebo Posted November 7, 2020 Author Share Posted November 7, 2020 Sorry I've tried adding a photo but it tells me the file type isn't allowed. I've got the Hornby R.8249 decoder, it's wired as follows;Orange - left brush armGrey - right brush armBlack - front bogeyRed - rear centre motorI've disconnected the light and their wiring whilst I wait for a PCB to replace the standard bulb. Link to comment Share on other sites More sharing options...
Chrissaf Posted November 7, 2020 Share Posted November 7, 2020 Whilst you wait for a reply, perhaps you would spend a few minutes reviewing the TIPs in the TIP page link below: TIP: As a newbie poster on the forum, just be aware that the 'Blue Button with the White Arrow' is not a 'Reply to this post' button. If you want to reply to any of the posts, scroll down and write your reply in the reply text box at the bottom of the page and click the Green 'Reply' button. See also – further TIPs on how to get the best user experience from this forum.https://www.hornby.com/uk-en/forum/tips-on-using-the-forum/ Link to comment Share on other sites More sharing options...
Chrissaf Posted November 7, 2020 Share Posted November 7, 2020 For the information of others. The Brian Rootham guide mentioned by the OP, can be viewed here: @Leebo,I happen to know Brian Rootham personally. I will email him and ask if he is prepared to look at your query and provide a response in this thread. Link to comment Share on other sites More sharing options...
Chrissaf Posted November 7, 2020 Share Posted November 7, 2020 @LeeboIt may be a physical issue with the motor itself, in that the current consumption goes up for some reason when you put it in reverse. There is a diagnostic check you could perform that would narrow down the area to focus on. If you unsolder the orange and grey wires from the motor and reterminate them the other way round. Now when you put the controller in 'Go Forward' the loco will try to go backwards due to the wire reversal. If RailMaster now reports the short when you have issued a 'Go Forward' command instead of a 'Go Backwards' command, that would prove that the issue is somewhere in the motor and not in the decoder or the rest of the loco wiring. If however, RailMaster still only gives the error condition when 'Go in Reverse' is selected then that would prove the issue is with the decoder. The semi-conductor output of the decoder is what they call an H bridge. It is technically possible for a semi-conductor component to fail in the H bridge that only affects one direction of travel. The diagnostic test I have documented above would prove it. Link to comment Share on other sites More sharing options...
Leebo Posted November 8, 2020 Author Share Posted November 8, 2020 Hi Chris,Thanks for that, I tried to reply yesterday but new member rules only allowed me the 2 posts. I've tried what you suggested and swapping the orange and grey wires and it still goes forward ok but when changing the direction in RailMaster to reverse, gives the short circuit error. I've tried 2 identical Intercity 125's and get the same result with both so like you say, either the decoder is faulty or I've gone wrong somewhere with my decoder wiring. Link to comment Share on other sites More sharing options...
Chrissaf Posted November 8, 2020 Share Posted November 8, 2020 It won't be the first Hornby decoder to exhibit this fault .... I suggest you assume it is the decoder and replace it. Link to comment Share on other sites More sharing options...
Leebo Posted November 8, 2020 Author Share Posted November 8, 2020 Thanks Chris, replacement decoder ordered, I'll let you know how it goes Link to comment Share on other sites More sharing options...
Chrissaf Posted November 8, 2020 Share Posted November 8, 2020 Even if it doesn't fix the fault, you will have a spare one for testing purposes in the toolbox. Always handy. Link to comment Share on other sites More sharing options...
Leebo Posted November 10, 2020 Author Share Posted November 10, 2020 Hi Chris,New decoder installed and runs forward and back like a treat. Thanks again. Leebo Link to comment Share on other sites More sharing options...
Chrissaf Posted November 10, 2020 Share Posted November 10, 2020 😎 Glad its sorted, sounds like my decoder H bridge fault diagnostic test was spot on. Link to comment Share on other sites More sharing options...
Leebo Posted November 10, 2020 Author Share Posted November 10, 2020 Well over my head but spot on it was 😆 Link to comment Share on other sites More sharing options...
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