Before sending your Digitrax mobile decoder in for repair try these simple steps to see if you can “bring it back from the dead” and save a trip to the shop and possible repair charge.

If you find you need to send in an item for repair, click here For Digitrax Repair Procedures and Information

The most common "repair" problem with decoders is really not a problem at all!

Customer quote: "I would like to thank you for the repair service provided last November. I was having a problem with a DZ120 decoder, which I had installed in a KATO NW-2 switcher. It appeared to run at one speed only. I replaced it with a DN140 and it worked fine. I sent the DZ120 decoder to Digitrax with a check for $17.00 to cover repair. I was amazed when I received the re-programmed decoder and the return of my check for a "no charge" repair."

The decoder we received from this customer had been programmed with CV values that caused it to run the way it did. The good news/bad news is that with DCC you have to be careful what you ask for because the system will give you just that, exactly what you programmed it to do. It's good news if you want to fine-tune your loco's performance. It's bad news when you program a CV by mistake and can't work out what you did! We see a lot of decoders that have this "problem." The moral of the story is that before you send something back for repair, check the programming in your decoder and re-program it if necessary. If you send a decoder like this to us, we will happily reprogram it and return it to you along with your check. The problem is solved but you have been without your decoder for up to 3 weeks.

Is the loco on powered track?

If the throttle is indicating that track power is off, turn track power on.

1. For DT100, DT200 & DT300 press RUN/STOP and the + UP ARROW key to turn on track power.
2. For DT400 press PWR followed by the Y+ Key to turn track power on. Track status indicator on the command station should be ON.

Test for adequate track power around the layout with the “Quarter Trick”

If your track does not have adequate power supply to the locomotives, then the DCC signal won't get through either. Take a quarter or screwdriver blade and go around your layout creating electrical short circuits across the rails every 3-6 feet. Your command station will beep and shut down as each short circuit you create is detected (Zephyr shows a blinking display instead of a sound). When the short circuit is removed, the booster will return to normal operation. If this does not happen, then you need to add more track feeders so that the signal/power is adequate all over the layout.

Can you select the loco on your throttle?

If not, the loco may be in use by another throttle or it may be part of a consist (do you see a cn in the display when you try to select it)? See your throttle manual for procedures to release the loco from other throttles or to remove it from the consist so you will be able to run it on your throttle.

Do the settings in CV29, (the decoder configuration register) match the command station’s output?

Digitrax decoders are set up for running on a system that is sending 28/128 speed step commands. If your decoder is a 14-step decoder status editing will be needed to make the commands sent by the system match what the decoder is expecting. See your throttle and decoder manuals for information on status editing.

Does your throttle display show 'xFF' or ‘FULL’

This means that the system's capacity to handle operating locos is full.

The DCS50/Zephyr can run up to 10 addresses at the same time. When you have 10 addresses in use and try to add the 11th, the throttle will display ‘FULL’. You will have to release one or more of the 10 addresses currently in use from the throttle in order to run another address.

The DB150 that comes with Super Empire Builder can run up to 22 addresses at the same time. When you have 22 addresses in use and try to add the 23rd, the throttle will display ‘FULL’. You will have to release one or more of the 22 addresses currently in use from the throttle in order to run another address.

The DCS100 that comes with Super Chief Sets can handle up to 120 addresses at the same time. The DCS100 is set for 22 addresses at the factory. When you have 22 addresses in use and try to add the 23rd, the throttle will display ‘FULL’. With DCS100, you have two options: 1. You will have to release one or more of the 22 addresses currently in use from the throttle in order to run sthe 23rd address. Or 2. You can consult your Super Chief manual for information on changing this to 120 if you are exceeding the limit often during operations.

During decoder programming, the FF or FULL message may also be displayed if the loco you are trying to program has to many loads attached. If this is the case, you need to remove some of the extra loads to allow the decoder to be programmed. This happens most often with locos that have many lamps installed or where the lamps are wired directly to the track pickups.

Was the loco running and then suddenly stopped?

If the decoder is very warm it may be in thermal shutdown. Let it cool off and see if it starts up again.

Check for localized track problems (see quarter trick above)

Are there burn marks on the decoder?

You'll need to send it in for repair!

Have you reset any CVs since the last time you ran the loco?

If so, go back and change them to their default values (see below) and then try to run the loco. It is possible to set acceleration so high that it will take 10 minutes for the loco to start moving and this makes it look like the decoder is not working.

If all else fails!

Reset Configuration Variables (CVs) to factory settings values as follows:

Series 3 decoders (123, 143, and 163 all scales)

1. Place the locomotive with the decoder to be tested on your programming track and put your system into programming mode.

2. Set CV08=08. This will reset all of the CVs to the factory settings with the address at 03.

3. Replace the loco on the layout and select 03 on your throttle to run the loco with the decoder.

4. If the decoder/loco does not respond the decoder will need to be repaired/replaced.

5. If the decoder responds, set the address to the one you want to use and retest the decoder using the new address.

6. If the loco responds, check the decoder manual for guidelines on resetting the other CVs before setting any CV values. If the decoder does not respond, check the manual for instructions on setting the address and reset the address.

All other Digitrax mobile decoders

1. Reset your decoder to the factory settings by going into program mode and resetting the following CVs. (Be sure to reset the CVs don’t just read them back.)
AD2=03
CV02=00
CV03=00
CV04=00
CV05=00
CV06=00
CV19=00
CV29=06

2. Replace the loco on the layout and select 03 on your throttle to run the loco with the decoder.

3. If the decoder/loco does not respond the decoder will need to be repaired/replaced.

4. If the decoder responds, set the address to the one you want to use and retest the decoder using the new address.

5. If the loco responds, check the decoder manual for guidelines on resetting the other CVs before setting any CV values. If the decoder does not respond, check the manual for instructions on setting the address and reset the address.

Strange Behaviors of Locomotive Lights

1. If you can’t control the operation of the lights in your locomotive, be sure that the decoder is programmed to match the speed setting used by your command station. All Digitrax command stations are set for 28/128 speed step mode. All Digitrax decoders are shipped programmed to 28/128 speed step mode. You may have changed your decoder’s programming when performing the decoder test procedure. In any case, if you are not able to turn the locomotives lights on and off, you will need to change CV 29 to a value of “06” to have proper light operation when using a Digitrax command station in its optimum 28/128 speed step mode. Refer to your command station manual for programming instructions. Additional information about programming CV29 is also available in your Digitrax Decoder Manual.

2. If you have a Digitrax Series 3 decoder and you can control the lights but not the motor, check for a motor short circuit. These decoders are designed to shutdown motor operation when a short is detected to prevent damage to the decoder.

3. If your Digitrax decoder blinks the lights when it is put on DCC track for the first time, remove it from the track immediately because this behavior indicates a short circuit in the installation. Check the installation and correct the short circuit to prevent damage to the decoder.