Fleischman N scale BR212

Fleischman N scale BR212/V100

M1 decoder Installation

Photos and text by Duncan Nisbet of St Bernardin, Ontario, Canada

Hints:

1. Do not make this your first decoder installation; it takes care, time and experience.

2. Plan your installation carefully.

3. It is best to test wire and run the locomotive before cutting any wire leads for the motor or functions/lights, so you will have lots of spare wire to work with for the final cut and fit, and can determine front and rear.

4. Test run the installation after the motor is wired and before you wire the lights, a surprise here is more easily corrected.

5. Extending a short wire is possible, but it is far easier to cut to fit when you are sure of where to go, and how to run the wire. It can also cause problems re-fitting the body.

The project:

To fit a DCC decoder into this model, which as no room under the hood, and is very tight in the cab.

The work area:

The frame is quite large compared to the body (which it fills), with an attached circuit board, and there is no room in the cab (circled) for a decoder.

The frame will have to be milled to create a decoder pocket.

The motor and drive-shaft/gears make milling the frame a tricky thing (plan ahead and take care).

First cut:

The best place for the decoder is in the long hood, under the circuit board, just above the worm gear.

Here is the resulting milled frame.

You can mill the frame with a small bench grinder, cut-off tool and files (This step took about 40 minutes, being careful and slow).

Take great care to only remove as much material as needed for the thickness of the decoder.

In this case the M1 being slightly thinner than most decoders is a distinct advantage.

The space is very tight so you will probably have to trim the decoder shrink-wrap to the minimum, which saves about ½ a millimeter of length (Having a goof proof warranty is a comfort here).

The frame was milled that the forward retaining lugs for the circuit board were kept, though this is not really needed, and would provide another millimeter, so you would not have to trim the shrink-wrap on the decoder.

Almost there:

The circuit board before modification.

The modified circuit board with the decoder installed in the frame.

The capacitor, choke coil, and mounting set for the bulbs were removed.

Traces were cut at the indicated points, and a hole cut for the decoder wire pass-through, as shown.

Be careful:

From this view you can see that space is tight.

It also shows one very critical point in the installation.

The decoder MUST be installed with the flat side of the decoder uppermost; this uses the large electrical component on the down side of the decoder as a spacer pad to keep the decoder clear of the top of the worm gear.

If you don't do this, the worm gear will bind on the decoder, which could be unfortunate for both.

Wiring:

The Gray and Orange wire are soldered to the circuit board on the pads hidden by the resistors.

The final wired installation.

Note the black jumper wire from the feed clip isolated when the traces were cut.

Warning: Double check the wiring for correct connection and potential shorts, and especially check the lighting connection if you need a resistor to control the voltage. Getting the wiring wrong results in a very nice “N” gauge fireworks display, and potentially a fried decoder. This happened in a different installation and a non-TCS decoder (no goof proof warranty).

Notes:

There is so little room under the hood that you must make sure that the wires are as flat as possible, with no crossovers except in the cab space and the resistors are placed so that they are in the cab space, and remove any excess plastic from the hood area.
If there is shrink tube or wire crossovers under the hood you will probably have trouble getting the body back on.
The normal bulbs have been replaced with LED's (Golden White type). These are three-millimeter LED's and are a very close fit in the old bulb mounts; you may need to open up the bulb mounts a bit with a file or drill.

The final product: