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How to Rescue a Faulty Decoder

Posted by on Dec 18, 2014 in Tips Decoders and Installations, Tony's Tips |

What to do When Decoders are Not Working:

The ability to change a decoders CV settings gives an engine a multitude of customized features. Many modelers only go as far as changing the decoder’s default address from 3 to the cab number. A common fear is that if you enter the wrong value, lose control, you may end up in limbo without the ability to recover or correct the problem. Also, sometimes a track short circuit may cause some decoders to get corrupted and not respond correctly. Good news! There is generally a simple solution. Most decoders have a way to restore the decoder CVs back to factory default settings … much simpler than trying to figure out which CV was causing the problem!

According to the manufacturers, many of the decoders returned for repair could have been rescued if they had been first reset to factory settings. I talked with one decoder manufacturer who said at least 33% of their returned decoders are “fixed” by using the simple reset procedure.

Since the factory reset is not in the NMRA DCC standards or recommended practices, each manufacturer can do their own thing. If you do not know the manufacturer of your decoder, you can try reading CV8 on the program track. This is a read only CV that has the manufacturer’s ID number (numbers shown in decimal).

Here is a chart that lists the most common IDs and reset procedures. For other decoders check the manual for CV and value used to reset to factory settings. All these decoders do support Ops Mode programming and can be reset on the mainline assuming you have control of the address.

If you do not have control of the address use the program track.

Manufacturer Mfg. ID in CV8 CV for reset + value
Lenz 99 CV8 = 33
NCE 11 CV30 = 2
Digitrax 129 CV8 = 8
LokSound (ESU) 151 CV8 = 8
Train Control System 153 CV8 = 8 or CV30 = 2
SoundTraxx: DSDLC, DSX
Tsunami (1)
141 CV 30 = 2
CV8=8
MRC (New) (2) 143 CV125 = 1
QSI (1) 113 See Below

(1) Generally requires PowerPax, Programming Track Booster
(2) Generally is not reliable in Read-Back

How to Reset a Decoder

Start by determining the decoder manufacturer. On the program track read CV 8. Compare the number with the above chart for the ID (if you have a QSI decoder [ID 113] see the information below). Then write to the matching CV the value as shown in the chart (writing a number to CV 8 will not change the value in CV8 when you read it back). When resetting the decoder, it may respond by flashing the lights or tooting the horn. Resetting a decoder will change the address back to the default of 3. Try the decoder on the main line using address 3 to be sure everything is okay. Then you can start your programming.

QSI Decoders

The Broadway, Atlas, and Lifelike equipped with QSI (ID 113) DCC sound engines use a different reset procedure. Check the manual that came with the engine. Some use a magnetic “wand” for the reset. If there is no “wand” then open the engine or access hatch and find the reset jumper. Remove the jumper and restore the track power. There will be an audible acknowledgment from the engine at the end of the reset sequence (usually 3 toots of the whistle/horn). Replace the jumper and test out using address 3.

If a “wand” is present, locate the internal reset reed switch and place the “wand” over it for a moment. When track power is restored the engine will go through its reset procedure and let you know when done. To find the internal reset (reed) switch, place the engine on active track. Slowly move the “wand” over the top of the engine or tender until the engine alerts you, audibly responds, by a message.

QSI also has a software reset using the following multi step procedure:

(1) Place engine on main track if it is still responding to its address. If not responding you may need to use the program track.
(2) Set CV49 to 128
(3) Set CV50 to 255
(4) Set CV56 to 113
As engine resets you will hear the 3 toots. Test out the locomotive using address 3.

QSI also has some selective resets. Refer to the DCC Reference Manual for this information.