Installing a DCC decoder into a Bachmann K3 Steam Loco
Click on each image for a more detailed view
Last updated 29 March, 2020

This installation really is one of the easiest in a steam loco as the engine is DCC ready. The most difficult part is refitting the body on to the chassis ensuring that the bar connecting the loco to the tender and the rear sand pipes are correctly located.

Before installing chip into any loco it is advisable to check the current being drawn by the loco.

Removing the body from the K3


The body is secured to the chassis with just 2 screws, one at the front and one at the back. The rear screw also holds in place the bar pulling the tender. When the rear screw has been removed, slide this bar out from between the chassis and the body. With a flat headed screwdriver gently lever the front part of the chassis from the body. The chassis fits very tightly to the body, but be careful not to use too much force. You will need to gently lever at the back when the front has been levered up a few millimetres. Keep alternating between the two ends until the chassis seems to be free of the body.


Location of NMRA socket in K3

The loco is DCC ready, having a socket installed in the middle of the loco. Gently lever the dummy plug out of the socket.

This installation used a TCS M1 UK decoder, one of the smallest decoders on the market, with a short harness for UK locos.

It is also possible to disable the capacitor by cutting through one of the legs securing the capacitor to the circuit board with a pair of wire cutters. This action is recommended to improve the performance of the loco with a decoder installed, but be aware that disabling the capacitor may invalidate your warranty.

K3 with decoder wires tidied

Firmly push the plug attached to the decoder into the socket, being careful not to bend the pins. Make sure the decoder is correctly orientated, with the orange wire at the front left.

It is suggested that you do any programming of the decoder, before replacing the body.

The decoder wires will need to be folded so that the decoder can be pushed into the void in the front part of the boiler between the weight and the outer casing. The TCS M1-UK decoder is ideal for fitting into the space available.


K3 rear end

Replace the body carefully making sure that the single sandpipe, which has a loop in the centre of it to go around the screw hole, is correctly located and that the bar linking the loco to the tender is slotted in before replacing the screw. Note the different sizes of screw shown in the photograph opposite and where they should be located.

NOTE: The TCS DP2X-UK decoder, a plug and play no wires decoder which fits most UK locos, will NOT fit into this loco.


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