New to DCC- any advice?

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Brian
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Re: New to DCC- any advice?

#11

Post by Brian »

I'm sorry to contradict a fellow forum member, but having a ring of wire or track will not confuse anything! Its a myth that unfortunately and occasionally pops up. If your model railway was around 1/2 mile long it may, possibly cause a issue, but in reality a layout is no where near that length.

If it were true and it isn't, all those people with simple basic ovals of track would be complaining :o
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Gareth 73
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Re: New to DCC- any advice?

#12

Post by Gareth 73 »

Contradict away I'm only going on experience. Had a ring main on layout had problems with a certain brand of cheap sound decoders where noise in the dcc signal would affect them. Quite worrying when locos just move off on their own and nothing but turning power off would stop them. Was told to break the circuit both track and ring main and now they don't seem to do it. Coincidence? Perhaps.
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Brian
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Re: New to DCC- any advice?

#13

Post by Brian »

Gareth 73 wrote: Thu Feb 17, 2022 8:32 pm Contradict away I'm only going on experience. Had a ring main on layout had problems with a certain brand of cheap sound decoders where noise in the dcc signal would affect them. Quite worrying when locos just move off on their own and nothing but turning power off would stop them. Was told to break the circuit both track and ring main and now they don't seem to do it. Coincidence? Perhaps.
Sorry your uncontrolled run aways are not caused by the Bus or rails forming a ring! :o
It is/was all to do with the decoder seeing the full DCC rail volts as being a DC voltage and taking off at full speed until the rail power is removed!
How to overcome this?...
A) Ensure all rail tops and loco wheel rims are cleaned very regularly.
But in the main...
B) Turn Off DC operation in each locos decoder via CV29. Reduce the current value set in CV29 by 4. So if for example CV29 is read as being 6 make CV29 value 2. :D

Having a ring is a total myth and should never be quoted as the cause, unless you have an extreamly large layout, In which case the layout should be broken up electrically into DCC zones, each powered from its own Booster.
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Gareth 73
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Re: New to DCC- any advice?

#14

Post by Gareth 73 »

They never went full speed some would just crawl which if I didnt notice caused various incidents. Perhaps it was just the fact they were tts chips as no other chip did it. And like I said it must have been coincidence that they started behaving. So sorry for giving bad advice just personal experience. Doesn't really matter as I'm swapping most of em out due to the limitations of the tts chip anyway
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Brian
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Re: New to DCC- any advice?

#15

Post by Brian »

Ah that makes sense re uncontrolled slow running, the Hornby TTS decoder is not supplied enabled for DC operation. :D
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dtb
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Re: New to DCC- any advice?

#16

Post by dtb »

the DCC CV29 Calculator, maybe helpful to the thread or other instances for members, just bookmark the link if necessary,

http://www.2mm.org.uk/articles/cv29%20calculator.htm
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