Tender Driven Loco Wires

[david_biggs]

I am putting a DCC decoder in a tender driven loco (King Edward I). I have removed the capacitor, the red wire from the tag on the motor, however when I treid to remove the black wire from the motor I ended up with all of the wire, the other end has a triangular tag. I have looked at service sheet 104 and I can see the locations of the red wire but no sign of the black wire. My question is where does it come from.

Thanking you in anticipation

David

[WilliamDavid]

Doesn' t the tag on the black wire fit onto the motor chassis, which itself is part of the circuit?

[96RAF]

You are as well stripping out all the wires, ensuring total isolation of the motor brushes from the wheels and wiring from scratch according to convention.

Rob

[david_biggs]

Thanks for your prompt replys. My basic understanding of DCC is Red and Black rails Orange and Grey motor. Red is sorted in so much that is screwed to the chassis and this in turn does one rail. The Black should be going to the other rail, but where does it connect to its rail connection

[Fishmanoz]

This loco (Service Sheet 112) uses a common arrangement with power being picked up from the left wheels of the loco and right wheels of the tender (Service Sheet 104 as you say).  I found all of this info in the Hornby Guide. 

 

As shown in the sheets, the path from wheels to the motor brush connections is via uninsulated wheels to chassis (LH wheels are uninstalled on the loco, RH uninsulated on the tender).  From the loco it then goes via the draw bar to what must be an insulated connection on the tender chassis and then via the (red?) wire to the RH brush connector. As drawn in 104, there is no other wire, hence David’s problem.  As drawn, the LH brush connector must connect to chassis and the uninsulated RH wheels. 

 

Given there are actually 2 wires, the LH brush connector must be insulated from the chassis and the 2nd wire run from the brush connector at one end to a convenient place on the metal chassis where there will be some form of tag for the wire to clip to.

 

So you are looking for a tag on the metal chassis to which clips the far end of the black wire from the motor connection. Unless I have this logic all wrong. SoT would know for sure but he doesn’t always look at DCC topics. 

 

PS.  Given you have two wires connecting to the motor, both brush connectors should be insulated from chassis but good practice is to measure with a multimeter to make sure, as per Rob’s post. The penalty for not checking and getting it wrong is a blown decoder. 

[The son of Triangman]

Red wire screwed onto the chassis, oh dear I foresee disaster!  The red wire comes from the tender contact pin, you simply remove the spade terminal from the red wire, put a bit of heat shrink on the wire, solder the red decoder wire to the red wire, slide heatshrink over the join and the job is done for the red wire.

 

The black wire runs from the left hand brush contact(looking at the front of the motor) to a cast lug on the motor casting.  The red wire to the tender brass contact pin. Positive power is picked up via the brass pin.

 

A word of warning on some early ringfield motors there is a belt and braces arrangement, some castings have a cast pin under the left hand brush contact. The contact is best gently moved away from this pin and heat shrink put on the left hand brush contact, failure to do so will fry the decoder.

 

The grey decoder wire goes to the left hand brush contact and the orange wire to the right hand brush contact. The red wire from the tender pin goes to the red decoder wire and the black wire goes to the little black wire that fits a cast lug on the cast motor housing.

 

Providing you have a loco in good running order before hand and it hasn't been messed with then this should work well.

[david_biggs]

Thank you everyone fot the valuble info I will use it as soon as I have time. Once again , thank you.

[The son of Triangman]

Glad to be able to help

[david_biggs]

/media/tinymce_upload/98e983876868cf270cf4dcf486d53c9c.jpg

Sorry for the enormous picture But it shows the pins that I can see. The second pin from the top was where the wire looped around before disappearnig into the darkness. The scratch marks are where I have been trying different posts. Am I missing the plot(or post)

[david_biggs]

/media/tinymce_upload/0f130dadd6e784a3f03c5dac76abf5a3.jpg

Here is the culprit. These are the only posts I can see. The pin second from top is where the black wire loops around before going into the darkness. Am i not seeing something

[The son of Triangman]

Stage 1. The Black continuity wire normally runs from this lug on the cast chassis to the left hand brush contact.  You keep the black continuity wire on this lug and fix the other end of the black wire to the black wire on the decoder.

/media/tinymce_upload/9dbb52a265a35646e4d07d68e68896e0.jpg

 

[The son of Triangman]

Stage 2.  On earlier ringfields there is a cast pin on the cast motor block, it comes through a hole under the left hand brush contact and makes a connection. you need to put heat shrink on the left hand brush connector(the tab that sticks out).

The Red "circles" show the area where the continuity pin is located and comes through an oblong hole in the plastic faceplace to make contact with the bottom of the left hand brush contact.

 

/media/tinymce_upload/fd897ec96a4b0e5b5c067b6bb9aff05f.jpg

[The son of Triangman]

This picture shows the area that needs insulating. /media/tinymce_upload/48bf41b1158e177c57cb33cd2a7c0d36.jpg

[The son of Triangman]

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