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DCC Conversions: Steam






Roco S160 .. 21 August 2018
LB&SCR E1 (Dapol 00 Terrier conversion) .. 25 August 2018
REE S100 .. 25 August 2018
Rivarossi S100 .. 30 August 2018


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Roco S160


The Roco model of the S160 is a pretty fabulous thing. I have never owned a model built to such a high standard, nor one with such exemplary running qualities. Everything is pretty much 'faultless', but looking back at how much I paid for it, I suppose the model should be pretty good. Roco sold the model in two versions, DCC-ready and with DCC sound. My conversion is to simply add DCC control; I am happy to live without the sound.


Roco supply decoders with their own branding, and cite four possible fitments in the instruction manual supplied with the model: parts numbers 10881 and 10883 (both PluX 22 pin), and 10880 and 10882 (both PluX 16 pin). I could only find the 10883 online so I bought one of these.


Installation is easier than many models:
1. Pull the tender away from the engine to release the coupler.
2. On the tender, remove the handwheel moulding beside the footplate.
3. Lift off the top moulding (this includes the front of the tender body and the moulded coal)




4. Remove the blanking plug and set aside - this will be useful if the engine ever fails to run and you want to know whether the problem is in the model or the decoder.




For a moment I thought was looking at the usual 21-pin interface. Then I realised, the connector on the model has socket terminals, and so the decoder must have pins. This is the PluX interface.


5. Insert the decoder:




Nearly forty quid for a tiny little circuit board, most of twice the price of anything I have bought before. Then again, when I look at this photo I see this particular decoder was not cheaply made. And for all I know, it may have been customised or remapped for Roco's model motors.


And then, when I put the model back onto the track, operation is sublime. I have never seen a model railway locomotive run like this in my life, not at a show and not on my own layout. Running begins with an almost imperceptible crawl at notch 1, and remains controllable throughout the speed range. It has all rather exceeded expectations, and if the money for a branded Roco decoder is buying something which works so perfectly out of the box then for me it has got to be better value than a cheaper decoder needing hours of fiddling around with CVs and chassis wiring to get a result.


These engines do not have lighting, so all the decoder has to do is to drive the motor. I have no idea of the differences between the different decoders. I am told, Roco decoders are Zimo items rebranded, and the succession of part numbers reflects product development by the manufacturer of the decoder.


The product presentation for the Roco decoder is different to the usual style from British suppliers. The decoder comes in a box with a moulded cardboard insert, some conductive foam, a scrap of double-sided adhesive foam, and a 40-page instruction book. The instruction book is in three languages, and actually explains what the functions do as a self-contained publication. It is a far cry from the usual British manufacturer's list of CVs with a note "see advanced" against everything looking moderately interesting. I guess, the bottom line is you get what you pay for.


LB&SCR E1 (Dapol 00 Terrier conversion)


When I built my LB&SCR class E1 engine, I filled the smoke box and the bunker with lead. This seemed a good idea at the time but it has taken away the two decent locations for a decoder.


The original Dapol chassis runs nicely with a wired decoder from DCC Concepts (their 'NANO' decoder), but finding a place to put this or another compact mid-price decoder has defeated me. Conceivably I might slip an N gauge decoder between one side of the motor and a side tank, but for the time being this engine will have to come out on "analogue days", along with the other antiques in my collection.


REE S100


I approached the task of dismantling my REE S100 with some fear of what might go wrong. It is a fine model with a great deal of detail, and not something I want to break. Fortunately a lot of the detail parts are metal and reasonably robust.


The instructions supplied with the model are technically correct, but here is the missing sentence: "the body is held onto the chassis by plastic pegs (dowels) at each end - two dowels on the back of the smokebox door and one on the back of the tail lamp". When you know this, everything is a lot easier:


1. At the front of the engine, remove the two handrails on each side of the smoke box. Mine were held in firmly with super glue and I pulled them out using fine-nosed pliers.


2. Lift out the smoke box door - the body shell is now loose at the front.


3. At the back of the engine, pull off the tail lamp. There is enough slack in the wires to let it come a few millimetres away from the model.


4. Lift off the body shell.


This is how REE build a chassis for an 0-6-0T. I have left the two handrails dangling from the buffer beam:


The decoder socket is a PluX16. Nearby there are two capacitors to keep everything going if there is a bit of dirt on the line. This photo also shows the working drive linkage to the lubricator, this is a feature I've not seen before:


REE recommend the Zimo MX630P for this engine and so I duly bought one of these. While Gaugemaster and Dapol manage to produce a list of CVs and Lenz put an 40-page booklet in the pack, Zimo provide a 70-page download. The funny thing is of course, the Zimo is plug and play and needed no setting up at all beyond turning off DC operation.


The difficult part of the conversion was refitting the body onto the chassis. The Zimo decoder stands around 0.5 mm taller than the designers of the model expected it to be. There are other compatible decoders available to buy, but having seen how well the Zimo drives the model I decided to modify the body instead. The body is cast metal, and I used a grinding tool in a mini drill to remove a little metal from inside the boiler. Afterwards I cleaned up with a cotton bud and then compressed air.


My efforts removing and refitting the front handrails removed some of the paint on them, I touched this in after I took this photo:


Performance is very good indeed, with predictable slow running and smooth acceleration and braking. The slow running does not go quite as slow as the Roco S160, but it is better than any other model I have. So if the Roco S160 defines the state of the art, the REE S100 finishes second place in the premier league of model train mechanisms.


Rivarossi S100


I found the instruction leaflet for the Rivarossi S100 the day after I did this conversion. Rivarossi expect you to use a wired decoder, with the 6-pin plug under the cab floor (where I put the decoder) and the decoder itself at the front of the model. Unfortunately, I was a bit mislead along the way ... I had enquired to Hornby, who suggested putting the decoder in the cab, and I had seen a very neat conversion written up in North America using a miniature decoder I could not find in the UK. So my mind was set on putting the decoder into the socket.


Moving down the food chain, my final DCC conversion is for the European version of the Rivarossi S100. This model has a DCC socket, but hardly any space to install a decoder. I read the specification and found the model has a 6-pin socket, and I bought a matching decoder by DCC Concepts. This decoder is quite a compact design, but opening up the model it looked huge. I settled on the Lenz 'Silver', and this is how I went through the conversion:


1. Pull the two large handrails out of their mountings each side of the smokebox door. Turn the handrails out of the way and pull off the smokebox door.


2. Pull off the chimney and remove the tiny, tiny screw underneath it.


3. It would now be sensible to undo the screw at the back of the model, behind the coupler mechanism. This goes into a plastic lug moulded onto the inside of the bunker. I couldn't work out how to reach this screw, so I lifted off the body from the front first, the lug broke open and the cab end released itself. (The broken lug seems to work like a clip to hold the body onto the chassis afterwards).


4. Remove the DCC blanking plug.


Here is the space provided for the decoder:


If you want to keep the false floor of the cab, the decoder has to lie flat in this space. Even the Lenz decoder, which is marketed for N gauge, is too long to fit into the space. So you have to decide whether the remove the floor of the cab, and look at the decoder where the model crew should be, or set to work:


5. Remove and discard the orange and violet wires between the LED tail lamp and the main pcb.


6. Unsolder and remove the chip resistor (marked "102" meaning "1,000 ohms") with enough care to preserve the land (the pcb contact) beside the pcb mounting screw. Discard the resistor.


7. Cut out the section of pcb still holding the chip capacitor - I used a cut-off disc in a mini-drill. Clean up.


8. Plug in the decoder and track test for running qualities. The front headlight should work (F0) but of course the rear one will not.


9. On the Lenz decoder, solder a fine wire onto the land for the "blue wire". Also trim the six pins so they are short enough to let the decoder fit snugly into the socket.


10. Solder a wired 1k resistor between the miniature pcb for the rear light and the land preserved at step number 6. The resistor needs to fit snugly against the end of the decoder so the body will fit back onto the chassis.


11. Solder a flexible wire between the same miniature pcb and the fine wire added at step number 9. I added a scrap of styrene to prevent any short circuits onto the pcb locations labelled SP1. Retest, the rear light should work as well.




Both of the lamps are of Italian patterns and are not prototypical for an engine running in Great Britain, and the conversion would be a lot easier if you abandon the rear lamp altogether.


Looking at the whole pcb, there is plenty of unused space:


Even the socket for the decoder could move across a few millimetres.


I did write to the manufacturer and asked for their recommendation, and their reply whilst prompt was to put the decoder in the cab. This seemed a rather unsatisfactory solution to me, so I went ahead with my modifications. A month later, I found the instruction leaflet, where the advice is to use a wired decoder on a 6-pin plug, the decoder going into the empty space in front of the motor. So really, I have done unnecessary modifications to the PCB. It seems a daft design to me, but hopefully the Lenz decoder will be trouble-free and I won't be needing to look at it again. The model runs well with the factory settings in the decoder.

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