Hornby OO Rocket with Zimo Sound

Kit: MX648; Rail Exclusive Mini Tablet

This is one of the more challenging sound installs! The key to this job is thinking ahead. There literally isn't a mm to spare so it is important to get it right otherwise you will have to back-track and things are never as good second time round.

Start by stripping the model to its component parts and prepping your decoder. For this we are going to use a MX648 with its harness removed so we can wire directly onto the decoder. The tender is quite tricky to break down. The Barrel just lifts off but the coal load needs more persuasion to remove. The most difficult bit is to gently push out the under carriage containing the cables. Whilst we don't need the part itself, care must be taken to remove it so we don't damage the tender body.

To add to our challenge, we decide to add a firebox LED too! This is an extra that is your choice to fit or not but it's really worth the additional effort. The front of the firebox is simply glued onto the motor housing and finally has two very fragile clips towards the bottom. You need to use a knife to slowly ease the firebox away without cutting or snapping it. Once it is removed you can drill a hole for a t0402 Led. There is conveniently a hole in the bottom to drop the wires through. When you're happy everything is in place just a small dab of glue is needed to hold the facia back in place.

Now we need to prep for the installation of the decoder. Under the tender there are 4 pickups, cut the front two off as there simply isn't enough room to keep them and the loco will run without them. Make sure you cut them off from the top side of the tender as we don't want any chance of them making contact with the decoder. We then need to cut 2 strips of 1mm plasticard to act as panels to hide the decoder. A Good match of paint is Citandel Flash Gitz yellow.

Next we need to wire the decoder. Since there is no room for excess wire we need to use as little as possible . This means we need to wire the decoder in a manageable way. Start by adding the speaker wires first, leave them quite long for now. Next add the negative of the LED to function 1 (FA1) and work back towards you. I find it easiest to add the motor wires and pickups from the engine last as these are quite short and the loco could get in the way if you did these first. The speaker wires can then be fed back into the barrel to install the speaker later. You would have used a resistor on the positive of the LED. Make sure there is suitable heat shrink around the resistor to protect the decoder - there is enough height now to sit this on top of the decoder providing you have not left too much excess. Then simply use two small bits of BluTack (NOT BlackTack as this could pull off the components!!) to hold the decoder in place by pushing the BluTack against the insides of the side panels you have made. Finally cut a piece of insulating tape to cover the decoder and wires.

NOTE: Yyou will need to add wires from the rear pickups - when you wire these to the decoder make sure there is nothing that is shorting, take time to make sure you are 100% confident with this.

Now pop the wheels back in place making sure that the remaining contacts make good contact with the wheel. You will find that one side sits in front of the wheel shaft and the other side sits behind it. This is really important to ensure a good reliable contact.

Now start to build back up the tender by adding the coal first and then the barrel. Connect the speaker of your choice and you have done it.

Photos and words courtesy of Alan Thompson. Contact Alan at AGR Models if you would like one fitted out like this!

Please note that these guides are provided as useful resources for you, as-is. YouChoos cannot be held responsible for errors in the information, or for any damage caused to your models or equipment if you choose to follow any of the steps detailed here.