Bulver Posted December 18, 2017 Share Posted December 18, 2017 good afternoon, everybody, I would appreciate some help with understanding how I managed to fry a decoder yesterday. I bought the TTS decoder for ‘Tornado’ a few weeks ago, and this weekend tried it on the loco. As a dry run, fitted to the engine, ran a bit jerkily, but sounds all worked. Unfortunately, the speaker cables are too short for the ‘Railroad’ version. I purchased a sugar cube speaker with the intention of fitting it in the smoke box area, disconnected the supplied speaker, and attempted to solder the new speaker to the wires. Whoops! Firstly, the speaker flew onto the soldering bit, immediately pulled it off, and attempted again, same result. Re-tried, managed to complete this, fitted the decoder to the loco, zilch! Tried the original non sound decoder, loco ran fine, replaced with the sound decoder again, nothing, and realised it was very hot. Is it possible that the soldering problem caused this?. I didn’t realise how damaging my actions would be. A salutary lesson, but a shame that Hornby don’t fit slightly longer leads to suit all iterations of the model. Link to comment Share on other sites More sharing options...
2e0dtoeric Posted December 18, 2017 Share Posted December 18, 2017 Sounds like (sorry!) you've shorted out the speaker somehow, and fried the audio amp in the decoder, if not the whole decoder.I hope you weren't using an 'instant heat' gun? They will fry anything electronic!Loudspeakers contain a magnet, and the bit of a soldering iron is usually soft iron, Magnets and soft iron stick together nicely. Next time fasten the speaker down to something, first!It could also have been an electrostatic discharge from the iron to the decoder. Did you touch the iron tip to something 'earthed' first? Probably not, and you've given the tiny transistors the equivalent of a lightning bolt! Link to comment Share on other sites More sharing options...
Bulver Posted December 18, 2017 Author Share Posted December 18, 2017 Thanks, Eric, guessed that my actions caused this. The soldering iron is gas powered, but didn’t think of earthing the bit prior to firing up. I will try again, soldering the leads to the speaker first, then joining them to the leads from the decoder. A somewhat expensive lesson, eh? Think the whole decoder has gone, which is a shame. Thanks once againRod Link to comment Share on other sites More sharing options...
Howbi Posted December 18, 2017 Share Posted December 18, 2017 Have you tried re-connecting the original speaker to prove the decoder has failed or not?..........HB Link to comment Share on other sites More sharing options...
Bulver Posted December 18, 2017 Author Share Posted December 18, 2017 Hi, HB, thank you for your suggestion, which I haven’t tried yet. I will give it a go tomorrow, I haven’t done it earlier, as the decoder seemed extremely hot when I took it off the connection board. Fingers crossed, eh? Link to comment Share on other sites More sharing options...
Chrissaf Posted December 18, 2017 Share Posted December 18, 2017 Gas powered soldering iron !!!.If you are going to solder the tiny connections on a decoder board, you need the right tool for the right job. A fine tipped Electric soldering iron no more than 15W power rating..It has just got to be more cost effective to spend a few quid on a suitable iron than keep on replacing heat damaged decoders. Link to comment Share on other sites More sharing options...
96RAF Posted December 18, 2017 Share Posted December 18, 2017 I use a 1.5mm tip on an Antex 15w mains iron for decoder pad soldering, but have also had good results using a Lidl battery powered highlighter sized iron.Rob Link to comment Share on other sites More sharing options...
Bulver Posted December 18, 2017 Author Share Posted December 18, 2017 Agreed, Chris, but that was the only iron I have, also, didn’t solder on to the decoder, only the speaker. Have to invest in a new iron, methinks. (And a new decoder!) Thank you for the advice re power rating of irons etc. Doesn’t detract from my comment re Hornby ensuring that the product suits the range, though. Thanks for the pointer, Rob, I will visit Lidl to see if they have anything to suit, Bought the gas iron from Maplin, will look there, also, for alternatives.Rod Link to comment Share on other sites More sharing options...
96RAF Posted December 18, 2017 Share Posted December 18, 2017 As usual Lidl only have these things on offer now and again, however you can find them onlineSoldering iron Other makes are available but can be more expensive. Re the speaker wire length, when questioned about it Hornby said that the TTS decoders all come from the same production facility whether for retro or loco pre installed end use, hence running two lines one for locos and one with variable length wires for retro kits wasn't an option. The retro instructions clerly state that the wires should be extended as required and preferably at the speaker end. I sympathise about the speaker jumping onto the iron. It took me by surprise first time it happened. After that it was masking taped to the bench.Rob Link to comment Share on other sites More sharing options...
Bulver Posted December 18, 2017 Author Share Posted December 18, 2017 Thanks for comments, Rob. I have found an identical iron to the Lidl Model on amazon, plus mains powered Models as recommended by you and Chrissaf. Re the speaker cable length, I know that Hornby state that wires should be extended, and I did work on the speaker end only, went nowhere near the decoder, Oh well, an expensive lesson learned.Rod Link to comment Share on other sites More sharing options...
Traincliff Posted December 29, 2017 Share Posted December 29, 2017 Just a thought that I don't think has been mentioned. Was the sugar cube speaker the same impedance as the original Hornby speaker? I don't know what the tts one is but if for example the original is 8 ohms and the sugar cube 4 ohms then the amplifier could have overloaded and blown. Just looked and cannot find impedance mentioned in Hornby sales spec but no doubt one of our learned friends will know.Still waiting for my class 47 tts chip! Link to comment Share on other sites More sharing options...
Chrissaf Posted December 29, 2017 Share Posted December 29, 2017 Extract below taken from TTS decoder installation guide, states that TTS speaker should be 8 ohms at 1W../media/tinymce_upload/c568424033143ba0ac19d35f9f9bf074.jpg. Link to comment Share on other sites More sharing options...
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