Loco will not run in DC mode after changing CV29 Value

[96RAF]

@deem

The basic decoder wiring code (ignoring Hornby's all black wires) is RED and BLACK to the TRACK, ORANGE and GREY the OTHER way - i.e. to the motor.

Please check your connections with a multimeter regardless of colour of wires in use.

[Deem]

@96RAF

I have 2 Hornby R3171, one with original Hornby wiring and one was modified by the previous owner,

Original Hornby wiring was:

Motor had black wire soldered to top connection

Motor had Grey wire soldered to bottom connection

After checking that and listening to my fellow modeller I just swapped the wires on eBay item and all of sudden everting falls into right place.

Your suggestion is correct by the way as well.

Regards

[Fishmanoz]

Deem, glad that suggestion worked and now all as expected.

For new locos that are DCC ready, plugging in a decoder the correct way around (pin 1 being orange decoder wire, not grey decoder wire which is pin 5), it should just work correctly. If you install your own decoder and solder directly, then check on default 03 with the body off and, if it runs in reverse, swap orange and grey decoder wires.

If you or a previous owner has installed a socket, you can check similarly that the connections from the socket to the motor are the correct way around by the same test as above - install decoder correctly, pin 1 orange decoder wire, and, if it runs in reverse, swap the motor connections from the socket (just as you have done).

Colin, orange and grey wires can be found in the harness of every non-direct plug decoder you have. Whatever colour any manufacturer uses to run from socket to motor, they are extensions of those orange and grey wires coming via the plug and socket. Apologies if my words conveying that were unclear to you.

The complete standard pin designations and colour codings can be found at https://www.brian-lambert.co.uk/DCC_Page_1.html#Bookmark11 and going to Decoder Installation.

[96RAF]

Going back to basic DC. With the controller set to fwd and positive feed connected to the right rail in the direct of loco travel, negative to the left rail, the loco should run forward. Once that is correct any conversion to DCC following the wiring code should also end up correct.

[ColinB]

I think we have done this one to death, but 96RAF which locos have you been looking at. I don't think I have ever seen Orange and Grey wires going to the motor on a steam loco and I have repaired an awful lot. As I was saying earlier generally they are both black. Your are right with the red and black. It gets even worse with the locos with the socket in the tender, all wires in the tender are either red or black, red for one side and black for the other. When you come to the loco all the wires go to the 4 way connector and they are all black. The only ones I can think of that might be orange and grey are the small tank engines. I assume they use read and black as it is cheaper in production to limit the type of different wire. There is a photo of an A3 Flying Scotsman insides on another thread, surprise wires are black except for the red pick up wire. Trouble is by telling people they are orange and grey means someone will open up the loco and be immediately confused. In fact if you buy a replacement socket from Hornby pre wired, you will never guess what colour the wires are? Yes red and black.

[ColinB]

It appears Hornby do use grey and orange on their 4 pin connector for the 0-6-0, I have have just looked at a spare brand new motor I bought, perhaps this is where the confusion comes from?

[96RAF]

There is no confusion in my head Colin.

The colour code quoted is the universal standard for DCC. I did not say any production loco would be so wired and I even qualified my statement by exempting Hornby’s all black wiring.

As you say it is done to death.

[ColinB]

If you buy a 6 pin socket off of Bachmann, Laisdcc or DCC concepts it does in fact come with the right colours. Probably the Hornby 4 pin does because they probably buy in the sockets with looms all ready wired. As I said before I can see why Hornby use all black, when I used to work on avionics generally the backplane used all the same colour wire. It is a bit of a pain as when you disconnect the wires from the motor unless you label them, it is so easy to get them round the wrong way. That is probably what happened with this guys P2, the person puts the new 5 pole motor in and just wires it up. The only way I tend to notice that they are wired up incorrectly is to run them against an unmodified loco, generally a new one. I cannot believe we are still discussing this. One Dapol loco I have, I think it is the class 73, they miswired the whole lot so to get the lights to work properly you have to reverse the motor connections. It even says it in the instructions. I suppose I am unusual especially since I worked in software most of my life, I tend not to change CVs unless I absolutely have to.