Chuffing Billy Posted January 13, 2020 Share Posted January 13, 2020 Is it possible to hard wire a TTS Decoder into an old loco produced before DCC was ever thought of ?I've got a number of 'old' A4 locos and I'd like use the Hornby TTS decoder. The new locos have 8 pin sockets, which these locos don't have.Does anyone know if it's possible to hardwire them in and if so can they explain how or point me towards where it is explained ? The DCC section on this site explains how to hardwire an 8 pin chip plus lights, but not TTS.Apologies if this has already been covered on here, but having scanned through the 136 pages of postings on DCC matters, I must have missed it.........Thanks for your help, Chuffers Link to comment Share on other sites More sharing options...
Flashbang Posted January 13, 2020 Share Posted January 13, 2020 While the answer is Yes it is possible to hard wire them you really need to be cautious as the TTS decoder has very low motor current handling which could be exceeded or run close too causing the decoder to shut down or worse burn out! Red and Black to wheel pick ups, Orange and Grey to the motor.If lights are fitted the Blue wire is common Positive to all other function wires which are switched negatives. Generally White wire to front white lights and rear reds and the Yellow wire to front reds and rear white lights then these lights automatically swap around with direction of travel. Green wire is to any auxiliary lighting such as cab lights. Speaker is wired on its own. Which I believe are two purple or pinkish coloured wires. Link to comment Share on other sites More sharing options...
jane1707819582 Posted January 13, 2020 Share Posted January 13, 2020 You will need to do a current stall test first off . this wiil tell you the current the motor will pull .give the loco,s a good service first and ensure there is no faults running on D.C. DCC will only amplify any issues. If the stall current is less than 500 ma or 1/2 amp then you will have no problems . isolation of the motor is key to any DCC conversion . Link to comment Share on other sites More sharing options...
96RAF Posted January 13, 2020 Share Posted January 13, 2020 The TTS decoder is the same wiring as a normsl 8-pin decoder but it does not have the purple flying lead seen on say an R8249. Just use the diagram on the DCC conversions page of the main Hornby site.The speaker is already wored to the side of the TTS decoder and should not be detached. If you need to swap the speaker or extend the wires do so from the speaker end. Be aware if soldering near a speaker the magnet make grab your iron so tape the speaker down before attempting to solder it. Link to comment Share on other sites More sharing options...
Chrissaf Posted January 13, 2020 Share Posted January 13, 2020 The DCC section on this site explains how to hardwire an 8 pin chip plus lights, but not TTS..It makes no difference from a basic motor and lights point of view whether it is a TTS decoder or not. The only difference is the speaker and that is wired to the decoder on its own dedicated wires. The motor, pickup and lights wires are the same on both sound and non sound 8 pin decoders..But if you have to get the soldering iron out to hard wire any 8 pin decoder, then you might as well fit an 8 pin socket (loads pre-wired on eBay). Then the decoder is not affected and can be more easily removed and/or replaced for diagnostics and/or replacement. Link to comment Share on other sites More sharing options...
Howbi Posted January 13, 2020 Share Posted January 13, 2020 A couple of years ago I tried a TTS decoder in an old Hornby Dublo tank loco.........firstly I soldered the pick-up wires and motor wires to an eight pin socket and then plugged in the TTS with a sugar-cube speaker.........whilst it all worked it was not satisfactory as the greater current draw from the old motor had an adverse effect on the sound chip and the gearing to the driving wheels meant the chuff was seriously out of sync so the TTS was removed.............HB/media/tinymce_upload/513bfce9ca1775f0568dff9c99d59e58.jpg Link to comment Share on other sites More sharing options...
Ruffnut Thorston Posted January 13, 2020 Share Posted January 13, 2020 One other factor to be borne in mind. The steam TTS decoders chuff rate is set partly by the motor revolutions I believe. The Ringfield motor in the Tender Drive locos has a lot of gearing. The Hornby Railways Ringfield motor Tender Drive GWR 2800 2-8-0 that I tried with a TTS decoder was hopelessly out of sync. So much so that I abandoned that idea and fitted a non sound decoder instead. As I had first fitted an 8-pin socket, that was a quite simple exercise. 😀 Link to comment Share on other sites More sharing options...
Chuffing Billy Posted January 14, 2020 Author Share Posted January 14, 2020 Thanks to everyone who has replied. At least I know it's now possible, so I'll give a go and see how I get on.Kind regards, Chuffers Link to comment Share on other sites More sharing options...
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