zep75 Posted December 2, 2016 Share Posted December 2, 2016 Hi all I have one of these and the chip is showing a dead short, obviously the loco has speaker fitted The chip is 8 pin so presumably I can just find a replacement 8 pin sound decoder and do a simple replace Any ideas on such replacements as obviously the original tts was a generic one Help appreciated Thanks kj Link to post Share on other sites More sharing options...
Stephen Freeman Posted December 2, 2016 Share Posted December 2, 2016 Good morning, I'd be worried about why? If your layout is wired correctly with overload protection this shouldn't happen. Does this happen both on and off the layout? Has the thing ever worked, if not and it was DOA then perhaps a matter for Hornby? You don't want to go replacing chips until you know and have corrected the root cause. Link to post Share on other sites More sharing options...
zep75 Posted December 2, 2016 Author Share Posted December 2, 2016 Yes it previously worked Can't tell why All locos were boxed up and placed on layout only recently after a break all work fine this one caused a dead short - I have circuit breakers etc on ESU ECoS system It happens on the main and when only it is connected to the programming track Removing the decoder stops the short so it's definitely the decoder Link to post Share on other sites More sharing options...
smokebox Posted December 2, 2016 Share Posted December 2, 2016 Does the short go when a blanking plug is fitted instead of the TTS decoder? Link to post Share on other sites More sharing options...
zep75 Posted December 2, 2016 Author Share Posted December 2, 2016 Fitted a blanking plug and the short was not there so it looks like the chip Link to post Share on other sites More sharing options...
bgman Posted December 3, 2016 Share Posted December 3, 2016 I would seriously suggest speaking to Hornby. I have a loco which was wrongly wired ( not the P2 ) and would not operate correctly with any decoder. With the blanking plug no problem. There are several of their range which react in a similar way and as Stephen Freeman says, you are likely to keep blowing expensive decoders each time you try it. I hope you sort the problem soon. Me ne is currently on their workbench. p.s. I also use the ECoS and have other versions of my problem loco which I'm told were from an earlier batch and they are chipped without the above problem. Link to post Share on other sites More sharing options...
Phil S Posted December 3, 2016 Share Posted December 3, 2016 Have you got a multimeter? - preseumably YES because you have measured - or was that simply detected - a short? Check with meter, and no decoder or blanking plate plugged in; and measure from each wheel, to both chassis (hopefully open circuit) and each pin of the socket .... and ONLY the corner sockets, not connected to the motor, should show a (zero ohm) connection. The motor should show about 20ohms or more ( 1/4A running current ) IF any others show conduction, it s another Hornby wiring fault. BUT ALSO check BELOW the socket - when a decoder is plgged in, that the pins, projecting through, are not touching the chassis!! (Roco often have a piece of plastic here, as they often have the motor case below the socket) - a good tip is to insert a piece of plastic or insulting tape beneath the socket. Link to post Share on other sites More sharing options...
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