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DCC starting out - I'm not a techy but so far its been worth it!

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3 hours ago, Izzy said:

I think I am correct in saying that the whole idea of pcb’s and decoders with plugs that just, er, plug-in, is to try and make the whole DCC thing easier/simpler for all users. But this all relies on the said pcb’s being well designed and properly constructed. Sometimes neither happen and then it all falls down.....


As an example a while ago I fitted sound into a Heljan W&M railbus. This has a 21pin socket pcb. The matching Zimo sound decoder is the MX644D. The warranty states that the speaker wires must be connected to the pcb or said warranty is invalidated. There are sockets on the pcb for various aspects, including speakers. These are lettered/numbered. But there is no schematic available to say what each is for, nor do Heljan provide available plugs for these sockets........


Or like the early Hornby class 50s which had the lights wired wrong on the PCB. :unsure:

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50 minutes ago, Pete the Elaner said:

Or like the early Hornby class 50s which had the lights wired wrong on the PCB. https://www.rmweb.co.uk/community/uploads/emoticons/default_unsure.png


And then blew up decoders......

Then folks complained to the decoder suppliers that the decoder had failed..........................


Or to fit a 21 pin decoder to the first batch of Dapol 73's you actually have to fit it upside down.


Or fit a decoder in some Heljan diesels - test and all is well. Put the body on and it presses the underside of the pcb onto the metal chassis with various - usually release of the magic smoke - effects.


Fit a 8 pin decoder in the normal - non-sound/DCC ready release, but a 21 pin in the sound fitted version and then make it impossible to swap bodies around because one has the cab lights wired negative common and the other has positive common. (Hornby 60 with ESU sound)


Or fit a decoder socket and leave virtually no space for a decoder unless it is a solitary make/model number - there are lots of examples of that.


I'm sure there are more examples of non-DCC-friendly models, but that's probably worth a topic on it's own rather than here.


The manufacturers are getting there with making it easier to fit DCC - but it's taking longer than it should.


All of which simply make the transition to DCC more difficult than it should be.




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17 hours ago, Izzy said:

Fitting the standard Zimo 21 pin will be no issue I feel.... just getting it apart in the first place........ It’s a weighty model that runs well, but access to fit a decoder is not that easy.

I have fiddled about with mine a bit to make the lights directional and only one side which are now red to be faux tail lights, ( ordinary oil lamps were used on them rather than the fitted ones as per DMUs in this time era), but I did this as I had to strip it right down to convert to P4. The wiring is a right old game....


However, all you need to do is get the main body off to be able to take the blank out and plug in the decoder... you’ve been down this route before! 

You remove the roof horns - they lever upwards - remove the screws underneath. Un-hook the door handrails, and the body should...maybe...come off, lifting upwards. There are clips you release by pulling gently outwards as you do this.... This then reveals the cast metal sub-structure the body is on, with the pcb in the middle of the roof section.


I haven’t yet put a post about all this on my RTR conversion thread, ( sorry can’t seem to post a link here via the iPad). I have long meant to but just never got around to it. Perhaps I should. I’ll see if I can find the shots I took at the time. They might help explain things a bit more.




I decided to bottle it I'm afraid due to the many comments about getting this model apart I bought one brand new retail and have had it sent to AGR who are rapidly becoming my DCC go to guys to fit the decoder and set it up.


I should get it in app 2 weeks all set up...….tried and tested!

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