Installing a DCC decoder in a Bachmann Class 24 or 25 Loco
   
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Last updated 2 July, 2014

 

This is about as easy as it gets - Bachmann have made their Class 24 and Class 25 DCC-Ready which means you can just plug a decoder straight in. No soldering is needed, in fact no tools at all other than the cross-head screwdriver you need to remove the body from the chassis. There isn't even a need for these instructions, they're just here to show those thinking about taking the plunge how easy it can be.

 

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All you need to install a decoder into this loco is a cross-head screwdriver, a decoder with a standard NMRA plug and the double-sided sticky pad supplied with it. The decoder I used way back when I took the photos was the Lenz LE104XF, but these days I'd tend to use the more highly specified Lenz LE1024E. If your loco is brand new like this one then it's probably a good idea to test-run it before proceeding in order to check everything is OK.

An equally suitable decoder is the TCS DP2X-UK which is a plug in decoder with no wires.

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To be honest the most difficult part of some conversions is persuading the body to part company with the chassis. Not so here, Bachmann have sensibly joined things together with 4 screws that can be found in holes underneath the chassis. Undo these screws (circled in red in the photo) with a cross-head screwdriver and put them to one side - you may have to turn the bogies a little to get access to the holes. If you then put the loco back onto it's wheels and lift the body it should come away with ease. If not then just grab hold of the fuel tanks underneath the loco and once again lift the body.

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Once the body has been removed you should have unrestricted access to the circuit board where you will plug the DCC decoder. For later reference the front of the loco (or number 1 end as it's known) is the end with the two crew figures in the photo and the equivalent end of the body is that with the large grille and fan in the roof. After the conversion your loco should move in this direction when you tell it to go forwards.

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A close up of the circuit board shows the orangey coloured dummy plug fitted to the DCC socket. Just pull it out and you will see...

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...the actual socket (the black thing with 8 silver holes in the centre of the photo) where the DCC decoder will plug. Keep the dummy plug somewhere safe just in case you ever want to convert the loco back to conventional control. At this stage it's a good idea to snip off the orange capacitor labelled 'C1' on the circuit board as this is not required under DCC operation. I forgot to do this for the photos - sorry!

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Normally you'd just plug the decoder in at this point and finish up, but with this particular loco you might want to make a simple safety provision to prevent mishaps later. Bachmann have unfortunately left the pins under the circuit board (circled in red in the photo) a little on the long side and these might touch the chassis block in the future causing a short circuit. I've never had this happen personally, but better safe than sorry!

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If you loosen the screw (circled in red in the photo) a little you can swing the circuit board to one side and stick a piece of insulating tape to the chassis to prevent short circuits. Then just swing the circuit board back and replace the screw. You could also trim the long pins back with side-cutters, but either way 30 seconds work is all it takes to guard against future problems.

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The moment you've been waiting for - simply plug the decoder into the socket. It's as easy as that. Pin 1 (with the orange wire) should go towards the top right in this photograph, but if you get it wrong the loco will merely run backwards - you won't blow anything up!

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Finally, stick the decoder down using the supplied double-sided sticky pad. Make sure none of the metal components can short out against anything in the loco and that the wires don't foul anything. In the case of the Class 24 and 25 this mainly means making sure nothing obstructs the 3 holes (circled in red in the photo) on either side of the chassis.

Before putting the body back on the chassis it's as well to check that everything is working. The safest way to do this is to put the loco on the programming track and try and read information from the decoder - the instructions for your particular DCC system will tell you how to do this. If all is well (and I've never yet had a problem) then pop the body back on and secure it with the 4 screws. They'll be on the floor somewhere....!!!!

This guide first appeared on the ElectricNose web site belonging to Steve Jones and is reproduced here with his permission

 

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