Dr diesel Posted November 2, 2009 Share Posted November 2, 2009 Hello all Decided to chip a DCC ready Bachmann class 25 yesterday. Straight 8 pin plug in job. I put the loco on the programming track and tried to read the address, the loco then moved off along the program track followed by the dreaded blue smoke. After a lot of investigation it was found the PCB board on the underside had a direct link between pin 4 black wire track pickup and pin 5 grey wire motor input. In DC mode this is not a problem as the blanking plug links these two connections, But of course is a no no when it comes to DCC. After scraping away the offending link on the board and putting in a new chip all was well. So, a word of warning, always check everything with a multi meter even the PCB board. Regards Jeff Link to post Share on other sites More sharing options...
Kenton Posted November 2, 2009 Share Posted November 2, 2009 If a factory fault would it not be better to return it and claim the cost of the chip destroyed by the "not fit for purpose" as in not "DCC ready" as claimed on the box ? Too late now of course. Link to post Share on other sites More sharing options...
Dr diesel Posted November 2, 2009 Author Share Posted November 2, 2009 Hello Kenton Yes I agree sending it back would be the correct thing to do but after the exhaustive search finding what was wrong,and the fix being fairly easy, I decided to forgo the loss of the decoder and put it down to experience. The warning still stands though, check the boards. Regards Jeff Link to post Share on other sites More sharing options...
RMweb Gold Dagworth Posted November 2, 2009 RMweb Gold Share Posted November 2, 2009 I put the loco on the programming track and tried to read the address, the loco then moved off along the program track followed by the dreaded blue smoke. Which system are you using? This shouldn't happen as the programming track should not have enough power to damage decoders and you should get an indication from your command station that there is a problem before the loco is subjected to full track power. Andi Link to post Share on other sites More sharing options...
Dr diesel Posted November 2, 2009 Author Share Posted November 2, 2009 Hi Andi Prodigy 2 It was trying to read the decoder and due to the inbuilt short in the pcb it was somehow getting motor drive, however I was looking at the display and not the loco which trundled along the program track and across the insulated fishplates and onto the main sidings with full track feed then puffff. Jeff Link to post Share on other sites More sharing options...
Dr diesel Posted November 2, 2009 Author Share Posted November 2, 2009 Hi Andy I once measured the output on the program track while programming and I got a measurment of 11.2 volts Seems a bit high don't you agree Regards Jeff Link to post Share on other sites More sharing options...
RMweb Gold Dagworth Posted November 2, 2009 RMweb Gold Share Posted November 2, 2009 Hi Andy I once measured the output on the program track while programming and I got a measurment of 11.2 volts Seems a bit high don't you agree Regards Jeff It's not so much a low voltage as a low current output that shouldn't have enough power to do any damage to the decoder. Andi Link to post Share on other sites More sharing options...
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