DCC for Flying Scotsman

[Shuntmaster]

Converting my tender driven Flying Scotsman to DCC. The helpsheet shows how to do it with a four wire setup. My tender has only two wires black and red broadly as sevice sheet 131. I am clear about Orange and Grey decoder wires to the suppressor. -  But do I simply connect Black to Black and Red to Red?  - Red wire on tender goes to the loco drop link and track conductor seems to be in the loco chassis.

Your kind assistance appreciated.

[96RAF]

With a ringfield motor one brush is live to the red wire, which picks up from the right rail normally and the other brush is live through the chassis and axle via the wheels on one side only to the left rail. The loco may pick up on both wheel sides.

 

When converting to DCC you must ensure this brush to chassis connection is isolated often by way of a nylon screw in lieu of the left hamd metal screw or by insulating a small pin that presses on the left hand brush spring plate.

 

This isolation is essential before you go any further. The decoder black and red wires then connect to these existing matching colour loco wires, which are disconnected from their motor bogie connections. As you say the decoder orange and grey go to the motor brushes and you can snip off and bin the capacitor as suppression is taken cre of by the decoder.

[Fishmanoz]

There are at least 3 different Ringfield arrangements used by Hornby, some of which have the chassis connection via the LH motor brush holder and if so that must be isolated using the nylon screw or you'll blow the decoder, and some that don't. Google Brian Lambert and go to his DCC pages where he covers the different arrangements. 

[Shuntmaster]

Thanks guys!  Found exactly the info I was looking for on the Brian Lambert pages (thanks Fishmanoz) What a good resource.