Using very small mechanisms on DCC

[eastworld]

Some of the very small N gauge chassis (also used for 009) have no space for a decoder in them. I was wondering if on a small and very simple layout where only 1 loco was ever in use at a time, would it be possible to wire a decoder into the main feed to the layout instead of having it in the loco? This would also mean that the locos used would not need a decoder each, as in effect whatever loco was on the track would have a decoder wired into it.

 

Just wondering if this would work/has been done?

 

I should add that I know very little about DCC but to me the above should be feasible.

 

Stu

[34theletterbetweenB&D]

It works and has been done. Basically you are running the layout from a PWM DC controller.

[Nigelcliffe]

Yes it can work.  But, you need to know a few things before doing it.  The main one is "what happens if you create a short on the layout" from a derailment or any other cause of a short.   

 

With quite a lot of decoders, the result of shorting the motor outputs (which is what you're using) will mean the blue smoke comes out of the chip, and its destroyed.   Some decoders have short circuit protection (typically European brands), but even then you're abusing what its supposed to protect.   A better approach is to have a current limited supply to the decoder in question, and then a decoder which can handle a larger current than the supply delivers.  Thus the decoder won't ever be at overload. 

 

 

 

And, I'd like to know what it is that doesn't have space for a decoder.  In most cases, its owner doesn't have the necessary knowledge about how to fit a decoder. 

 

 

- Nigel

[devondynosoar118]

Why not just run on DC if you never intend to run more than one or two loco’s? You can wire points and use a bus type set up to be DCC compatible later and just include a couple of isolating sections if you want to park a second loco or have more than one controller. If you later want sound and DCC all you would need to do is turn the sections on.

Some very old stuff with cast chassis blocks and no isolation can be more difficult, but there are plenty of newer examples on eBay if you want a small engine which will take a chip more easily. The Dapol pannier is just a plug in. Some second hand ones may already be chipped, saving a chore.

As Nigel has pointed out there are very few locos in N you can’t fit a decoder to, it just requires more creativity in where they go and more eye straining to solder them in. You can get sound and a chip in an 04 shunter so using a wired decoder as opposed to a plug in one should be fine in 009. Be aware that white metal bodies will need extra care as the decoder can short itself to death on anything conductive!

Edited October 2, 2018 by devondynosoar118

[WIMorrison]

I run H0e and have always managed to get a decoder into my locos, I haven’t tried to fit in sound like they do on many N Gauge locos and I know that there are several 009 locos now that have full DCC sound!

 

In some of my older models from Roco, Liliput and Bemo I have resorted to fitting the chip into the cab and sticking it to the roof with the wires running up the inside from of the cab - ROCO in their new DCC ready models use this approach with the chip mount in the cab (I like to think that they copied me )

 

A little bit of lateral thinking will get the chip in - just make sure you buy a mini version and not a full size decoder which I agree might be a challenge to accommodate!

[Phil S]

We have a large but lightweight transportable H0 layout which ONLY uses DCC control - by Roco Multimaus and Rocomotion Touch Screen - BUT we also have H0e H0m and H0f on the layout - ALL controlled VIA the SAME DCC handsets  - giving total convenience as we walk wirelessly around the layout - including accessories - so there is GOOD REASON to control the small locos VIA the DCC system: On this layout ALL the H0e and H0m are digitised, leaving only the H0f to control in analogue, in the way you are thinlking.    My loft layout has some H0e used by ancient locos which remain unconverted... and for which a dcc decoder - with current protection - is provided.

 

For the H0f we use 2 of the dedicated Busch Modules which are dcc decoders each with A SINGLE  motor output in the  -3V - 0V - +3V range, AND 4 'function button operated' sectional relay-power feeds to distribute it as required.  - we have these to 2 groups of tracks on which the 'mining'/field industrial 6.5mm (2ft) gauge trains operate 'manually' from our controllers because they are located on different baseboards.   THEY DO SUFFER from the usual analogue problems of needing very clean track (and the H0f is delicate) - but they get their grip from 'Magnadesion' as Tri-ang used to call it. Busch ALSO PROVIDE 'cutouts' which appear to be self-resetting PTC fuses?

 

IT IS ALSO STILL POSSIBLE to then have a simple automatic shuttle operation - many modules available - where the speed is set by the (busch in this case) controller output - and that section of track then shuttles whenever enabled  - I have such a module waiting to be fitted - the usual diodes are needed at each end.

 

Have you checked the voltage when your small locos are running at their desired maximum speed? If 3V, the Busch Module is ready made.

 

We also control 2   Magnorail H0 working (pedalling) bicycle tracks from Loco decoders - as this gives adjustable speed - from any handset - and direction control - we have found this much more reliable than simply switching the drive on and off which jerks the belt.  We will be expanding the idea to provide small boats with movement, and also, some skiers.

 

The Backmann Wickham trolley or Underground Ernies are quite small mechanisms  - but relatively simple to fit a small decoder to.

Edited October 2, 2018 by Phil S

[GoingUnderground]

Some of the very small N gauge chassis (also used for 009) have no space for a decoder in them. I was wondering if on a small and very simple layout where only 1 loco was ever in use at a time, would it be possible to wire a decoder into the main feed to the layout instead of having it in the loco? This would also mean that the locos used would not need a decoder each, as in effect whatever loco was on the track would have a decoder wired into it.

 

Just wondering if this would work/has been done?

 

I should add that I know very little about DCC but to me the above should be feasible.

 

Stu

You might find reading this recent thread http://www.rmweb.co.uk/community/index.php?/topic/136572-using-a-dcc-controller-to-power-a-dc-layout/ helpful.

[John K]

This subject comes up every few months.

Yes you can do it.

Is it a good idea? Probably not - there are very few 2mm scale models that you can't get a decoder into.

John K