Spireblade Posted February 23, 2018 Author Share Posted February 23, 2018 Just to check , I risked a standard decoder in it and all worked well so I'm very puzzled. I'm well upset about frying the TTS decoder and to be honest I doubt I will ever go down that route again. I simply dont have the money to waste on such fragile things. :-/ Link to comment Share on other sites More sharing options...
DEREK123 Posted February 23, 2018 Share Posted February 23, 2018 Hi Rob and SpirobladeRob .... you have restored a lot of confidence in myself ... thanks 😀I phoned Express Models again ( another Rob !! ... most helpful guy too ). I am returning what is left of the kit for him to look at and hopefully return restored.Spiroblade ..... What can I say ? . 😢 . ☹️ .. I know just how you must feel ... I have fried 2 x TTS decoders . And each time I have had no idea why ... Glad the Class 47 has survived. 😀I can only assume my problems were solder or short related. 🤔CheersDerek Link to comment Share on other sites More sharing options...
Chrissaf Posted February 23, 2018 Share Posted February 23, 2018 Spire, did you do a stall test on the loco before fitting the TTS. The TTS has a much lower 500mA motor current limit compared to the standard non sound decoder. Link to comment Share on other sites More sharing options...
Spireblade Posted February 23, 2018 Author Share Posted February 23, 2018 Errrrr no! I've not heard of that. What should I have done? Link to comment Share on other sites More sharing options...
Chrissaf Posted February 23, 2018 Share Posted February 23, 2018 A stall test (performed on DC without a decoder fitted) ascertains the maximum current that the loco will draw, so that you can check that it will be within the limit of the decoder motor output. Most modern locos don't really need to have a 'stall test' done as they are usually more frugal with regard to current consumption. Most decoders also have a motor current capability of 1 amp, so again it can be reasonably assumed to be OK with most locos..The TTS on the other hand only has a 500mA (0.5 Amp) motor current rating. If a loco is DCC ready and contains a DCC socket, then it is reasonable to assume that a 500mA motor current limit will be OK. It is more normal to only perform a 'stall test' on non DCC ready locos or older loco stock. But the age of the loco is not always a guarantee of what current the loco will draw. Given that you have fried the TTS decoder, it may be worth doing a 'stall test' on the loco just to see if excessive current draw caused it to fail..How to do the 'stall test' is described here:http://www.brian-lambert.co.uk/DCC.html#NORMAL.To reiterate again, you need a DC track supply and the DCC decoder removed to perform a 'stall test'. Plus a multi-meter capable of measuring up to 2 Amps DC current. Link to comment Share on other sites More sharing options...
Spireblade Posted February 23, 2018 Author Share Posted February 23, 2018 Thanks for that Chris. It is a purpose built TTS loco so should be fine althougb I will check it. Link to comment Share on other sites More sharing options...
Chrissaf Posted February 23, 2018 Share Posted February 23, 2018 In that case, I shouldn't bother. Either the TTS decoder was weakend by your earlier wiring issue with the short on the socket OR you still have some sort of problem with the way your lighting kit is wired. Link to comment Share on other sites More sharing options...
96RAF Posted February 23, 2018 Share Posted February 23, 2018 TTS decoders are self protecting on the motor circuit so it is more likely the function outputs that are fried as they are not self protecting. I would be closely checking the lighting kit wires added to the socket for solder bridges or even incorrect connection.https://goo.gl/images/iaRF0F A quick colour code check is to see if the wires on the decoder match up with those on the socket (All black loco wiring excepted).Rob Link to comment Share on other sites More sharing options...
Fishmanoz Posted February 23, 2018 Share Posted February 23, 2018 Chris, the 8249 is 500mA just like the TTS, so if you are replacing one with the other, there shouldn’t be an overload problem. With Hornby kit, you have to go to the Sapphire to get 1 Amp. Link to comment Share on other sites More sharing options...
Chrissaf Posted February 23, 2018 Share Posted February 23, 2018 Ooops! to lazy to search out the data sheet and check. Although I was thinking more generically when using the term 'standard decoder' i.e not just the Hornby brands, many of which have 1 amp as standard. Link to comment Share on other sites More sharing options...
Spireblade Posted February 24, 2018 Author Share Posted February 24, 2018 The Elite started to buzz just before the puff of smoke, I'm suprised it didn't cut out. I connected it back up to see what happens and there was another, smaller puff of smoke. There don't seem to be any issues with the standard decoder in there at all. Most likely I weakened it previously but I'm very wary of putting another TTS decoder in and killing that too.As for bridging on the socket, I rewired the whole loco due to all black silly thin wires and used a pre wired loose socket to save me from that issue. Link to comment Share on other sites More sharing options...
96RAF Posted February 24, 2018 Share Posted February 24, 2018 As I read the problem the decoder isn’t pulling enough current to trip the Elite protection, so the decoder dies.You,can use a coin across the rails to test the Elite but you are relying upon the decoder to self protect below that threshold, which it can on the motor side but not the functions/sound side.Rob Link to comment Share on other sites More sharing options...
Fishmanoz Posted February 24, 2018 Share Posted February 24, 2018 /media/tinymce_upload/124235a5c828afde5d9e3ce8911b3701.png Chris, every time I look at a TTS leaflet, I come away thinking something different about its max current specifications so I’ve posted it instead. It’s all very clear except for the sound being apparently magical in that it would seem to draw no current. My conclusion is that in piggy-backing sound onto an 8249 to make a TTS, they’ve given the sound part it’s own supply and not changed the 8249 part at all. The only trouble with that conclusion is the 4th function on a straight 8249 and where it’s 100mA is hidden. Link to comment Share on other sites More sharing options...
Spireblade Posted February 25, 2018 Author Share Posted February 25, 2018 Having slept on it I decided to take a risk and as a final "stick or forget it" situation, I took my TTS decoder out of my 47 and connected it in to my poorly 37. Waiting for imminent disaster and puff of smoke I must say that I'm delighted that it all worked. On the test track for 5 minutes and no issues.So, I presume that I must have damaged the 37 decoder somewhere along the line, and the rewire has actually been a success. Oh well, thankfully Hornby now do the seperate TTS decoders so I will have to pop along to my local stockist and replace the one I've killed.Thanks chaps. Link to comment Share on other sites More sharing options...
DEREK123 Posted March 1, 2018 Share Posted March 1, 2018 Hi Rob & ChrisI am getting the repaired kit ( loom ) back from Express and am preparing myself for fitting it to the "47" again.I need to buy the resistor you mention which ( if I understand correctly ) is soldered to the blue wire from the decoder and to the kit blue wire .... is that right ?I also need to know exactly what resistor I need to buy ? can you suggest a supplier ( Maplins is near to me )Can you help / advise me please ?Derek Link to comment Share on other sites More sharing options...
Chrissaf Posted March 1, 2018 Share Posted March 1, 2018 Maplins has just gone into administration. My local Maplins has ceased trading and the doors are locked and the premises are empty when I passed by the store this morning...1,000's of resistor suppliers sell on ebay. It was Rob (RAF96) not me that recommended an additional resistor in the Blue wire when using the Express Model kits in a TTS. But he didn't specify the value he used in this particulat topic thread. I seem to vaguely recall him quoting a 1,000 ohm resistor in a different thread..So basically you are looking for a 1,000 Ohm resistor sometimes also referred to as 1K Ohm or 1K0 Ohm that has a 1/4 watt power rating and can be made of several different materials. Carbon and/or Carbon Film are the two most common material types. The basic carbon resistors are the cheapest type.. Link to comment Share on other sites More sharing options...
DEREK123 Posted March 1, 2018 Share Posted March 1, 2018 Thanks Chris .... you're a star again !!Derek The Maplins website says that they are still open in Luton and Watford .... I'll find out !! Link to comment Share on other sites More sharing options...
Spireblade Posted March 3, 2018 Author Share Posted March 3, 2018 Derek, they are 1k resistors and I bought a strip of 25 for about £1.50 on Ebay. When I first aquired the loco I took it up to Olivias Trains in Sheffield who specialise in these areas. They looked at the loco and promptly handed it back saying that it couldn't be done. (I know it can be done, seen it on Youtube). They told me about the light flicker problems but I'm amazed with their reputation that they didn't appear to know about the inline resistors. Mind you, their interest is more with selling you a far far more expensive model. Link to comment Share on other sites More sharing options...
DEREK123 Posted March 3, 2018 Share Posted March 3, 2018 Spireblade , looks like we bought the same ( I hope !! ) Carbon Film Resistors 1/4W 0.25W - Full Range of Values - Various Pack Sizes( 152059712084 )Resistance: 1k OhmOnce I've fitted I will report back ... ThanksDerek Link to comment Share on other sites More sharing options...
DEREK123 Posted March 3, 2018 Share Posted March 3, 2018 Hi Spireblade(This is my 2nd attempt to post this reply ? )Thanks ... I too have ordered what sounds/looks like the same as you. Carbon Film Resistors 1/4W 0.25W - Full Range of Values - Various Pack Sizes( 152059712084 )Resistance: 1k OhmPack Size: 20Once fitted I will let you know how I got on.Derek Link to comment Share on other sites More sharing options...
96RAF Posted March 5, 2018 Share Posted March 5, 2018 I bought 100 1K 1/8W smd resistors along with 50 each white and red smd leds for less than a tenner post free from China. Arrived within 3 weeks. Couldn’t find them again though. Soldering them in is a different saga.Rob Link to comment Share on other sites More sharing options...
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