DCC Fitted Mallard doesn't work on DC

[Chrissaf]

Just received a hornby mallard DCC fitted and out of the box it doesn't work on a D.C. layout. What do I need to change? also shoUlster there be bare wires between the tender and loco?

[Chrissaf]

Just received a Hornby Mallard DCC fitted and out of the box it doesn't work on a D.C. layout.

 

As your Mallard is DCC Fitted ... that is to say a Hornby decoder has been fitted in the factory to the model prior to sale.

 

Could the decoder that has been fitted be 'by chance' a TTS sound decoder. If it is, then Hornby's current policy is to disable 'DC Operation' in the decoder. It should also be noted, that even if 'DC Operation' is subsequently 'enabled' on the TTS decoder, the Hornby TTS decoder can not make any sounds at all when operated on a DC layout. The sounds are only accessible under DCC control. This is stated on any and all TTS decoder data-sheets. It is another reason why Hornby disable 'DC Operation', as 'Hornby Marketing' do not expect users to purchase TTS locos to run on DC layouts.

 

If in the event that the decoder fitted at the factory is not a TTS sound decoder, then the Hornby disable 'DC Operation' policy may still apply, but given the second part of your question, it might also be a wiring issue ... read on below.

 

Given your later comment about 'bare wires'. It may be that the electrical path between the track power and the motor via the decoder is broken, preventing the loco from responding to DC [such a wiring fault will also disable DCC operation as well].

 

If there are four wires between the loco and the tender and these four wires connect via a white 4 way plug into a white 4 way socket on the tender. Then two of the four wires are used to pass track power from the loco pickups to the decoder in the tender and the other two wires take the motor feed power from the decoder in the tender to the electric motor located in the loco. If any one or more of the four wires is broken or any two or more of the wires shorted together, then the loco will not run.

 

What do I need to change?

 

To enable 'DC Operation' back on again [if it has been factory disabled], you need access to a DCC Controller capable of writing to CVs [Configuration Variables]. Whether that be a 'friends' DCC controller or one in a 'Model Shop' or local model railway club.

 

....also should there be bare wires between the tender and loco?

 

Wires? ... most likely Yes if the decoder is fitted in the Tender.

Bare Wires? .... No.

 

If there are four wires between loco and tender, then they should look like this and be terminated on the white plug. This X6113 part is available as a spare, should the wires get broken.

/media/tinymce_upload/dd694d4ce614c5f493dfd78f13c83a5e.jpg

These wires are very delicate and can easily be ripped from the white plug. Could this be what has happened to your loco. Could the white plug be sitting in the tender socket minus any wires connected to it. There is a special Hornby X6468 plug extractor tool for removing this white plug from the tender socket. Trying to remove the 4 way plug by pulling on the wires will very likely rip the wires from the plug, maybe not the first time, but eventually. This is precisely why Hornby sell the extractor tool.

/media/tinymce_upload/d91c7fef640642406e8ed3d6a59db3a5.jpg

 

The 4 way socket [Green box] on the tender to receive the X6133 4 way plug [Red box], looks like this example:

/media/tinymce_upload/bf5ce4e02a11044ad4e342e5d397eeb6.jpg

 

If you should need to replace the wiring with a spare X6113 part, it wires like this:

/media/tinymce_upload/ca8cbed9c1adbafa65f0daa67374b9e0.jpg

 

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