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Contents

• A cheap and simple DCC Decoder
• Suppression capacitor - To remove or not to remove
• Fitting the decoder to a loco that is not 'DCC Ready'
• Testing the decoder installation
• Programming the decoder for optimal running

Lenz LE1014W Ultra-Thin Drive-Select DCC Decoder
(LE1014W product manual)
$18.95 per decoder from Tony's Trains.

Feature Set:

• Selectable Silent Drive or Precision Glide Control
• Selectable for operation with 14/27, 28/55 or 128/256 speed steps.
• Operation on conventional DC layouts is possible or can be disabled.
• Provides 1A continuous motor current.
• Four function outputs, one rated at 500 mA and three rated at 150 mA each.
• Special lighting effects including directional, independent, adjustable dimming, Mars light, Gyro light, single Strobe, double Strobe, adjustable blinking and ditchlights.
• Support for Advanced Consist Control and Extended Addressing
• Support for programming on the mainline
• Support for all forms of programming as described in NMRA RP-9.2.3
• Programmable locomotive address, acceleration and brake momentum, speed curve and much more.
• Size: L 1.3" x W 0.63"x H 0.14" L 31.7mm x W 16mm x H 3.6 mm

This decoder is used because it works well, it is cheap and simple.

Update: Initially I had installed a Lenz LE1000 decoder, but the LE1000 does not support CV5 (Max speed) and CV6 (Mid point speed) neither does it support Speed tables. It didn't perform well and was erratic on my Layout. Notably when it came to managing the top-speed of the loco. Tony's Trains swapped these decodes for LE1014W ones that do support a speed table. So the loco now runs much better. Smoother acceleration and a much more realistic top speed. See the speed table settings below. The photos below show the LE100 being installed, but the wiring is exactly the same with the LE1014W.

For this article, we have here a Hornby Streamlined West Country class 4-6-2 34041 "Wilton" & tender in BR green. Reference number: R2218.

Built at the Brighton Works and originally numbered 21C41, 'Wilton' first appeared on the rails in October 1946 and was renumbered 34041 and liveried in BR green at the beginning of 1949. The Hornby model is liveried as 'Wilton' in its later days, complete with a cut down tender and the later BR emblem.

The model has no NEM socket so the decoder has to be installed directly to the pick-up wires and motor connections. There are no lights or other functions on this loco, so the function circuits of the decoder will not be used.

To remove or not to remove the suppression capacitor

European locomotives are equipped with a RFI (Radio Frequency Interference) suppression circuit, usually consisting of a capacitor and mini ferrites across the motor brushes. This is because of the high frequency signals that egress from the motors, can cause interference with household television and radio equipment.

Virtually all DCC decoders use a form of PWM (Pulse-Width-Modulation) to control motor speed.

Since the super sonic or high frequency decoders operate such that the high frequency PWM output is approaching RFI range, the suppression capacitor will start to act as a short, or suppress the decoders output to the motor.

Remove the capacitor. This will result in less current being drawn from the decoder, and improved performance from it. Again note, this is only applicable with high frequency PWM output decoders, normal PWM decoders will not be effected by RFI suppression circuits.

European and certain other telecommunication agencies require that RFI suppression circuits be installed, in the USA this is currently not a requirement. But note by removing the capacitor or disabling it, should cause no problems with RFI as long as a decoder is installed. The decoder's output will take care of RFI suppression on it's own.

At this point, certain locomotive manufacturers [Bachmann] have stated the removal of the suppression capacitor will not void the manufacturer's warranty when a DCC decoder is installed in it's place. Some decoder manufacturers [Lenz] also recommend the removal of suppression capacitors. Some manufacturers don't advocate removing the suppression capacitors [ZTC], but this is when using their decoders as they are designed to work with the original suppression capacitor in place.

The suppression of interference is what it's all about. I have had no instances where RFI caused any disruption to appliances in my place or for any of my neighbors.

At the end of the day, you can decide. If anything blows up, give your product manufacturer a call and see what they have to say. Please feel free to contribute your opinions or expert advice on our forums here.

Fitting the decoder

First connect the decoder to the pick-ups from the wheels of the locomotive:

• Red cable to the wheels, which in relation to the direction of travel, are on the right-hand side of the locomotive
• Black cable to the wheels, which in relation to the direction of travel, are on the left-hand side of the locomotive

Then connect the decoder to the motor connections:

• Orange cable to the motor connection previously connected to the right-hand locomotive wheels
• Grey cable to the motor connection previously connected to the left-hand locomotive wheels

Now connect the function, if required:

• Function output (white cable) to the bulb of the locomotive.
• If the function inside the locomotive (e.g. the bulbs of the light) is not electrically connected to the chassis of the locomotive (i.e; if they are, "potential free") then connect the other pole of the function to the blue cable.

Note: When using LEDs with the function output, note that the blue cable is the positive pole (longer anode side of the LED) and the function output the negative pole (shorter cathode side of the LED). The voltage at the function output is approximately 16 V. Please do not forget the necessary protective resistor on the anode side of the LED. The value of the resistor can be calculated by the formula R = V/I where I is current rating of the LED and I is the difference between the DCC track voltage and the voltage ratting of the LED.

For example: If the supply voltage VS = 16V, and you have a 3mm red LED (VL = 2.8V), requiring a current I = 15mA = 0.015A, R = (16V - 2.8V) / 0.015A = 880

, so choose a 1K

resistor (the nearest standard value which is greater).

Secure the decoder in a suitable place with double sided tape. If there is any chance of the components on the decoder touching anything, protect the decoder with an insulating sleeve.

Shield the soldered wires with electrical tape to prevent any shorts. Secure the excess wires with black tape to finish-off the installation. Coloured tape could show from under the body.

Testing the installation

Place the locomotive on the programming track (without its body on) and read the loco address (CV1). If you have installed the decoder correctly, you should now be able to read the address (3= factory default for the LE1014W). If you are not able to do so, it is possible that you have made a mistake when connecting the cables. Do not subject the loco to full running track power until you obtain the correct "03" address read-out.

If there is a problem, recheck your cables and connections.


Programming the decoder

This aspect of the installation is very important and often not looked at hard enough by the modeler. To get the best out of DCC, try and program you locomotives so that when they all run together on your layout, they look in harmony with one another and to the scale and feel of the layout. There is no point in all you locos running around at top speed, screeching off from a stop and then also stopping dead when the operator presses the stop button. It is much more pleasing to the eye of the operator knowing that the Gresley A4 is the fastest steam loco on the layout, the Merchant Navy class following behind, but still hold their own on the main lines. The shunting and branch line locos clatter along at a more sedate pace even when the controller is set to 'Max'. The Class 08 locos had a maximum speed of 27.5mph. For 00 gauge models, that scales down to just over 6 inches per second. Not that fast really.

Note: The default settings of the decoder will work fine and even if you use a Bachmann EZ Command these decoders will work out-of-the-box and you can still set the loco address and direction of travel. Bachmann users: If you have access to a decoder programmer or if you can visit someone with a programming controller, you can tailor your locomotive and use it with those settings on EZ Command. Once programmed, the settings in the decoder registers are stored permanently and will determine how the decoder controls the locomotive.

We use the configuration variables of the decoder or "CVs" to set up various operating characteristics of the decoder.

We simulate weight of the loco and resistance of the load by setting the Acceleration delay (CV3). Steam locos ease off and then build up speed as they pick up rhythm and momentum. We simulate inertia of the moving train by setting the Brake Delay (CV4)

The speed of the loco is governed by the voltage sent to the motor - starting out with it's initial starting voltage (CV2) and peaking with it's maximum voltage.

On most decoders, the speed curve is shaped by modifying maximum voltage setting (CV5) and the mid point voltage (CV6). The Lenz decoders don't use CV5 and CV6 so to modify the speed parameters of the loco, we must use a speed table. This is a series of voltages that are applied at the 28 speed steps enabling the loco to perform more prototypically. In 128 speed step mode the decoder internally averages the speed curve table to obtain the correct speed step value.

DCC CV Settings for the Streamlined West Country class Locomotive using the LE1014W decoder
CV1	41	Address (The loco number)
CV2	8	Minimum Speed (V Min at step 1)
CV3	4	Acceleration delay (0-15)
CV4	4	Brake Delay (0-15)
CV29	22	Default = 6, but to enable Speed curve selection, use a value of 22
CV67	Speed Curve Table (See below
to
CV94
The rest of the CV's are left untouched (factory default).

So there you have it. All should be working well. Please feel free to ask questions. You will find an immense amount of pleasure when you operate your locos on the same tracks independently from each other without having to worry about isolating the current to specific sections of your layout. Using this method to install and program your decoders, you can get the oldest locos from your collection to run alongside your most recent 'DCC Ready' locos. Have fun.


- September 2005

All text, photos & graphics ©2005 Doug Teggin - All rights reserved.