This Hornby D49 model arrived on the bench today from a modeller wanting sound and smoke installed having seen several conversions that I have done which we’re running at the Perth model Railway show a few weeks back. Nice straight forward model to convert. Tender body just clips off, and there’s just one small screw under the front bogie to remove the locomotives body. There’s a capacitor just in front of the motor. Now I personally always removed any that I find, others will no doubt say leave them in, but I have had locomotives in for repairs / servicing with running problems and have simply removed the capacitors and the faults were cured. Seuthe smoke generator no27 works well with both Zimo and ESU decoders, rated 10-16v and only needing one function wire to operate. On this model I have had to drill a large hole next to the fixing screw to allow the generator to be pushed up into the chimney, which also needed to be drilled out carefully to allow a nice slide fit. Use a small amount of a 2 pack adhesive to hold the generator in position. Next feed the two wires down through the boiler. As this model will be used by a younger rail enthusiast new to the hobby and DCC operation, I’m adding a front light which will be wired in parallel with the smoke unit. The idea is that smoke units will over heat and burn out if there’s no smoke fluid in them, so by adding a lamp it give the operator a visual indicator, if the light is on and there’s no smoke it follows that the smoke unit is ON and the fluid level needs topping up. So front light and smoke unit will be wired to the white (front light) function wire. Yes I know it’s not in the correct place but these accurate scaled lamps don’t like been handled so I’ve positioned it back closer to the boiler in the hope that any young hands handling the loco will not cause it to get broken off. Time to do the wiring, take your time here, when I first started doing these conversions I used to draw out a plan of the wires and their colours to help me. Basically with the Seuthe units you have a yellow and a brown wire, it doesn’t matter which way around they are wired, so in this install the brown will be the + positive and the yellow will go to the white function wire on the decoder. The lamp wires (LED) have to be wired for correct operation. The longer of the two wires is always the + so this can be joined to the brown smoke unit wire and soldered together. (Always best to solder these wires, I have seen installs done by just twisting wires together with insulation tape added, but a good soldered joint will alway give better reliable operation) The shorter lamp wire needs to have a resistor added, minimum 1k, but for more realistic light level I usually use 30k and some times 50k resistors. The first thing to do is twist one end of the resistor wire with the yellow wire from the smoke unit and then solder this joint, then solder the lamp wire to the other end of the resistor. You can see in the picture because the lamp wires are very thin, I like to twist them around the smoke unit wires for protection. After the joints are soldered I add heat shrink tubing, much neater than using electrical tape. You will also see that I have put a knot in one wire, this is to remind me which is the + wire when I thread them into the tender as I am using black wire. You can use two colours to make things easier to follow, I used to use black and blue, blue alway been the + to match the decoder blue + positive. After completing the install any blue wire showing between the loco and tender can be coloured in with a black marker pen. Obviously, if decoder and all wiring is located in the locomotive body then use what ever colours you have in your supply’s To get the two wires from locomotive to tender will be different on all models. On this Hornby model the cab floor has a flat section that sits firmly on the chassis so I had to use a handy hole which represents the firebox door. There is also a very handy slot in the tender body which meant the wires could pass through with no drilling of holes, which is usually the norm. A quick test to see how it looks before adding the decoder.....result ! The decoder of choice is a zimo mx645 8 pin with stay-alive from John at YouChoos - http://www.youchoos.co.uk/ The great thing about Johns web page is that you can listen to nearly all the sound files he has available before you buy, and if you need any alterations or tweaks he’s more than happy to help. So the D49 sound file is at :- http://www.youchoos.co.uk/Index-Shop.php?L1=Project&Item=LNERD49 I use small pieces of double sided tape to secure the speaker, a Brick13. http://www.youchoos.co.uk/Index-Shop.php?L1=Speakers The stayalive comes with the decoder pre soldered, so just the two purple wires to solder to your chosen speaker / speakers. The two wires from the locomotive are then soldered to the 8 pin plug where the blue + wire is and the white, front light function wire. Now if your not comfortable soldering to these small pins on the plug, simply cut the blue and white wires off the 8 pin plug and then solder the correct wires in the normal way adding heat shrink to protect the join. Refit the tender body, secure the locomotive body and then place the locomotive on your program track and set up the cab number to operate the loco. Once the cab number has been set, I then set up the “chuff” rate per wheel revolution. John supplies a full data sheet with all the settings and includes instructions on how to change some of the main cv adjustments such as chuff rate, main volume and speed settings. Operating the light function, give a nice glow to the lamp and a satisfying pop as the smoke unit operates for the first time. Next check your happy with the acceleration, braking and top speed.....but that’s a whole topic of its own. In most cases the decoder settings from YouChoos give straight out of the box operation. Normal disclaimer re YouChoos, I’m just a very satisfied customer.
