Brian-1c Posted January 23, 2022 Share Posted January 23, 2022 Hi, My friend has a Bachmann 3MT 31-981 (8 pin socket DCC ready) with a sound decoder fitted. It was bought 2nd hand, so the decoder make and model is unknown. The loco works fine, sound is good. However, when the power is switched on to the track, the loco toots and starts running, requiring the operator to quickly acquire the loco and bring it under control, from which point it all runs fine. This happens every time the power is re-applied, or if the loco is removed and replaced. Any ideas what might be changed to prevent this power on aberration please ? Thank you, Brian Link to post Share on other sites More sharing options...
RMweb Premium mezzoman253 Posted January 23, 2022 RMweb Premium Share Posted January 23, 2022 If you can, Check if DC running is on in CV29. If so turn it off. This can sometimes cause runaways and odd behaviour. Rob 2 Link to post Share on other sites More sharing options...
dasatcopthorne Posted January 23, 2022 Share Posted January 23, 2022 Have you left the 'whistle' activated on the loco. Check the F keys that are active. Dave. 1 Link to post Share on other sites More sharing options...
Hamburger Posted January 23, 2022 Share Posted January 23, 2022 CV 122 bits 0 & 1 ?? Link to post Share on other sites More sharing options...
Brian-1c Posted January 24, 2022 Author Share Posted January 24, 2022 19 hours ago, Hamburger said: CV 122 bits 0 & 1 ?? That CV can be different from make to make. But worth a look. Link to post Share on other sites More sharing options...
wiggy1 Posted January 24, 2022 Share Posted January 24, 2022 Before we go to far and change something that does not need changing we need to know what decoder make we are talking about, Zimo or ESU or other? I think some are assuming its an ESU but being S/H it could be anything. Wiggy. Link to post Share on other sites More sharing options...
pauliebanger Posted January 26, 2022 Share Posted January 26, 2022 (edited) Brian, If your friendis able to read CV8 the value will give a manufacturer specific code which can be checked against the NMRA list. https://www.nmra.org/sites/default/files/appendix_a_s-9_2_2.pdf From this we can see that ESU would report 151, ZIMO would be 145 and Hornby 48. Identifying the decoder type may help with diagnosing the problem you raise. Does your friend have more than one 'cab' as part of your DCC system? Is this loco under the control of another cab than the one being used? Best regards, Paul Edited January 26, 2022 by pauliebanger 1 Link to post Share on other sites More sharing options...
Brian-1c Posted January 26, 2022 Author Share Posted January 26, 2022 Hi Paul, Thank you, this is most useful, he has JMRI and a Sprog, so will be able to read CV8. That'll be a great step forward. He does have more than one cab, but the behaviour moves with each. I am sure he will check if one is "open" for that loco. 1 Link to post Share on other sites More sharing options...
Nigelcliffe Posted January 26, 2022 Share Posted January 26, 2022 5 hours ago, Brian-1c said: Hi Paul, Thank you, this is most useful, he has JMRI and a Sprog, so will be able to read CV8. That'll be a great step forward. If he has JMRI, the software will identify things, in most cases down to specific decoder hardware model and firmware release. No need to manually read CV8 and lookup NMRA numbers. That's what the software does for you (among a squillion other things). - Nigel Link to post Share on other sites More sharing options...
AlanRB Posted June 14, 2022 Share Posted June 14, 2022 Thanks for all the response on this topic. Brian-1c has identified the problem and my 3MT is now behaving itself. It has a LokSound decoder. My other 2 are Zimo. 1 Link to post Share on other sites More sharing options...
Brian-1c Posted June 14, 2022 Author Share Posted June 14, 2022 Right, for info, this was due to a latching function, F8. This produces the toot when pressed, but needs a further press to switch it "off" again. If the power is then removed, the toot will sound on power up. Ensuring that F8 is turned off also ensures that it will not sound when powered back on. This turned out to be an ESU (151) sound chip by the way, but I was able to repeat a similar situation with a Zimo sound chip in a different loco at the club in South Africa. In the case of the Zimo, F3 sounded the horn, but is latched on until pressed again. Like my friends loco, if that function left on, it sounds on power up, but ensuring it is turned off before powering down ensures it is quiet on powering up again. Hope this helps someone else with this. Brian Link to post Share on other sites More sharing options...
Brian-1c Posted June 14, 2022 Author Share Posted June 14, 2022 On 23/01/2022 at 18:08, dasatcopthorne said: Have you left the 'whistle' activated on the loco. Check the F keys that are active. Dave. Dave, you had it right. 1 Link to post Share on other sites More sharing options...
dasatcopthorne Posted June 14, 2022 Share Posted June 14, 2022 5 hours ago, Brian-1c said: Dave, you had it right. No doubt you are using an NCE Throttle. Glad it's sorted. Dave. 1 Link to post Share on other sites More sharing options...
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