Knowledge base: Decoder

Click here for the Function Decoder knowledge base

We test all decoders automatically, with a test bench and a dedicated software made by us. This software was improved over the years, and it is used to validate each decoders hardware before it gets the latest firmware and is shipped. All the decoders has to pass this test, and as a result they are validated. Later, before delivery, if it is the case, the decoders are updated with the latest released firmware. At that time, the basic functionality is tested again. Which means, only tested and working decoders leave our factory. If your decoder is not working anymore, some of the information below might help you solve the problem.

If you would like to know more about what we do to make sure only 100% working decoders are being shipped to our customers, read all about our test process here.


Output functions are also called AUX outputs. They can be a a physical cable (white, yellow, green, purple for example)  on the decoder or a pin on the cable-less decoders. If you want to assign another output function, you need to address the Lokommander II manual, pages 79 to page 93. Let's say you want the AUX3 connection on the decoder to become active when pressing F5, you have to enter the value of 16 in CV 40. (page 86) If you want F6 to enable AUX3, you have to enter value 16 in CV 41 (page 87). If you have value 16 in both CV 40 and 41, both F5 and F6 will activate AUX3.

A video to understand function remapping and how to remap can be found  here

1) Only front or rear light is on, when pressing light or Function key.

A: The Function keys can be programmed to enable different connected lights. If only the lights turn on on one side of the model, when you press a F key, but you want both front and rear lights to turn on, you have to tell the CV belonging to that key to enable that connected light as well. You do this by finding the CV value from CV 33 and onwards. It can take some figuring out to which connection each light is connected. But if you know that by default F1 activates AUX1, F2 activates AUX2 etc, it will be helpful to understand this.

2) Decoder damage protection

A: Under normal circumstances, there is no reason for the decoder to  be damaged, it has quite high current capability, and internal protection (on the motor outputs and AUX outputs too). In case of a short circuit, the decoder goes in a protection state, and disables the motor/AUX outputs. At the next start-up, first the short circuit are verified, if it does not appear anymore, the decoder will start a normal operation. If you can read out CV30, this gives information about the cause of the short circuit. Unfortunately, if you can't read out anymore the decoder, it is not possible to identify the cause.

3) The decoder has more than 1A

A: The motor driver bridge in our decoders are 2 Ampère, but we declared it for 1 Ampère. It is a safety measure. 

4) Train with decoder installed doesn’t respond

A: Test decoder outside of train. Directly to DCC steering unit or with a decoder tester like ESU Profi-Prüfstand. If it can be read, but doesn’t work as it should, enter value 8 in CV 8 to reset the decoder.

5) Use track input instead of blue (+) wire to connect light

A: You can connect each light using the white (front) and yellow (rear) wires as a minus (-) and one of the track connections as the + connection. Make sure both + cables leading from the lights will go to same track connection.

6) Using traditional light bulbs vs LED’s

A: f you are using old type light bulbs, they have a very low resistance in cold state, which could trigger the current  protection of the outputs. In this case we recommend to connect a series resistance (value of 22-33 Ohm )  with the light bulbs. If you are using LEDs, it will be not the case, but for LEDs a current limiting resistor should be present (this is present if the locomotive has LED lights from the factory). Between the power outputs (white/yellow wire) and track there will be almost the full track voltage.

7) Only one LED is on after pressing function key, even when CV value is set to show both

If you  have two LEDs each connected to a function output (for example OUT 1 and OUT 2) and you set the CV value of a function key to have them both turn on when pushing the button (fx value 3 for OUT 1 and OUT 2), but only one light is on, you might have both LED’s share one resistor. Normally its better to use separate resistors for each LED. If the two LEDs are not the same type may have different voltage drop, 

8) Setting light intensity of front light

A: If you like to change the intensity of a light source, which is linked to  one of the AUX functions, this can be set with a value from 0-255 in CV 48 to 57 inclusive.

9) Which decoder template to use in JMRI DecoderPro

A: For both Lokommander Micro and Mini there are default settings under: Create New Loco> Decoder installed> Tehnologistic (Train-O-Matic). If you don’t see it, update to the latest version of JMRI.

10) Front lights stay on, even when they are not activated

If you have a 6 Pin decoder, turn the connector around. Or you have caused a short when fitting the decoder. Check CV 30 for an error report. Try resetting decoder: value 8 in CV 8.

11) How to set long addresses in 3 steps

‍ Step 1 - You have to set the long address in CV17 and CV18 first. According to our tOm cvTool (a little helper), the long address of for example 1015 requires CV17 = 195 and CV18 = 247 (see image 1). The decoder will still react at this moment to its short address (3), since we have to configure it, that the long address will be used.

Step 2 - In CV29 (the main configuration CV), you will find the default value 14 (normal function mode enabled, DC and DCC mode enabled, and RailCom enabled) (see image 2). You have to set the so called bit 5, which will tell the decoder that his long address will be used. This can be done by writing the value 46 to CV29 (see image 003).

Step 3 - There is no step 3. At this moment, your decoder will react to all DCC commands transmitted to the long address 1015.

Image 1

Image 2

Image 3

12) CV value can’t be read.

Your digital control station might be too old. It requires RailCom implementation on the control station side.

13) With the throttle fully open, train doesn’t drive at full speed, but only very slow.

By default, F3 is set to enable shunting mode, but it will also enable AUX3. So if you have for example interior lights connected to AUX3, then you will also enable shunting mode. You can change the F key for the shunting mode by allocating another F key in CV 114 (check bits to set in manual). 0 will disable the shunting key completely (no F key assigned).

14) Slow start and stop is not working, even though a higher value is set in CV3 and CV4.

Probably function key F4 is active. By default, F4 is set to disable acceleration and deceleration, but also to activate AUX4. You can change the F key for the acceleration/deceleration mode by allocating another F key in CV 115 (check bits to set in manual). 0 will disable it completely (no F key assigned).

15) The decoder can’t be programmed with the Bachmann EZ Command Station

 The train-O-Matic decoders  can be controlled, but not programmed  with the Bachmann EZ (at  least the older, first version. We have not test it with the later EZ command station). 

Explanation: It seems that the Bachmann EZ is using a very ancient CV programming mode (Register mode), which is not anymore supported even by the standard. It is dating back to the beginning of DCC (click here to see a note about this). Our decoder, and others, are not supporting this CV programming. It is not required by the standard. Train-O-Matic decoders are not alone at this. Some other brand decoders will also not be programmable by the Bachmann EZ, but ESU decoders is an exception (latest version tested: v5).

16) Lights blink on one side / Lights flashing

It is obviously a short circuit condition. It is not necessarily a user error, can be caused by questionable connected capacitors, inductors (if it is an older analogue locomotive). Probably, if you test the decoder to another locomotive (which is already working), the decoder will work. You can check if there was a short by reading out CV30. 

Check the connection between the decoder motor outputs (orange and grey). No other capacitors or inductors are allowed between the motor armatures, chassis, etc. It is common to have some of these in the old analogue locomotive. They should be removed. The tracks should be connected directly to the decoder red/black wires. No other capacitors or inductors are allowed. This is how a DCC connection should be made.

Try this if you still experience the issue: Reset the decoder (value 8 in CV8), and without changing the speed from 0 (so no driving command for the motor circuit is transmitted) power up the decoder (switch on the track). Without activating F0 the lights should be off. The decoder when it is powered on, first is checking all outputs for a possible short circuit. So if there is no short circuit, the lights should not flash. After that, you can switch on the lights, which should light up normally, without flashing. If it is flashing, you have to check for a short.

17) One single Lokommander decoder controlling  two motors

Connecting two motors in parallel is not a good idea for any case. Except, when you power them simply in DC voltage. In the digital operation, the decoder is controlling the motors with pulses, and is measuring the back electromagnetic force (BEMF) to gather information about the rotation speed. In this way, with a close loop, it will have a control over the rotation of the motor. This is how the "load control" or "load compensation" works. Two motors will be never identical, the generated voltage (BEMF) will be different. They could kill reciprocally their voltages, or they can accentuate the measured voltage, which will give erroneous information to the decoder. So this is not a good practice, at all. 

However, the solution will work, but the performance will be never as good, as in the case when you are controlling the two motors with separated decoders. But sometimes, in engines with two close to identical motors, some locomotive manufacturers are still using this solution. They simply connect the motors in parallel.

At least, you should place two separate motor filters, separately for each of the motors. This is not a  missing feature of the decoders, it is against the operation principle of the motor control. Each motor should have its own controller.

As a final word, it is very important that the 2 motors should be identical type and they must be in good running condition. You should test them in DC first. If they are not running fine in DC, they will not either in DCC. 

18) Connecting a so called “Stayalive” (this is not the superior SPP/Powerpack)

It is described and illustrated in the Lokommander II manual, chapter 19, page 42/43. The direct connection of a capacitor would be possible, however we do not recommend this simple/rude solution. It is more correct to use the diode + resistor circuit while you are connecting the external capacitors to the decoder.

19) Using a Train-O-Matic decoder with a Chinese made coreless motor

If you are using a coreless motor, like the ones sold by Tramfabriek, set CV61 to 10 (PID; Proportional constant) to take full advantages of the running quality of the motor.

20) Decoder lock

The decoder lock is addressed in CV15 and CV16. A decoder will be unlocked only if the values of CV15 and CV16 matches. 

CV15: Enter the value of CV16 to unlock the decoder. This value in CV16 is set by you. Value 0 locks the decoder if CV16 is higher than 0.

CV16: Set the value to unlock the decoder with the value of CV15. Choose a value in the range from 1 to 7. Different locos can have a different lock value.