Hardwiring an R7274 decoder into a Hornby shunter Diesel Freight train pack

[Redfred]

How to hardwire a R7274 decoder into a hornby analogue diesel shunter

[Fishmanoz]

You say it’s analogue William but is it DCC Ready (fitted with a socket and blanking plug)?

If it’s not DCC Ready, I would start by fitting a socket. And I’d use an 8-pin socket, not 6-pin for the 7274 as there is a much wider choice of decoders available for 8-pin, including the Hornby R8249 which is the same decoder design anyway.

I’m sure someone will be along soon to tell you how to wire a socket. Or you could google Brian Lambert and find his instructions for doing so in his DCC pages.

[96RAF]

@fishy

R8249 is 8-pin

R7150 is 6-pin

R7274 is 4-pin

[ColinB]

There is probably very little room inside a shunter for an 8 pin socket, so I would use an 6 pin decoder. You can buy 6 pin decoder sockets off many companies, I would suggest the DCC concepts or Bachmann ones as the pins don't fall out so easily. As to the availability of 6 pin decoders, there are loads, as they are used extensively in N scale models. In my Bachmann shunter I did the conversion and used a Zimo decoder which is about the same price as the Hornby decoder but has a higher current rating and is a more robust product. As to the wiring, cut the two leads going to the motor. Connect the red led of the socket to the cut end not connected to the motor. connect the black lead of the socket to other motor lead cut end not connected to the motor. Now connect the cut end of the lead going to the motor to the orange wire and the other cut lead going to the motor to the grey lead. Now a good idea is to buy a 6 pin DC header, they are quite cheap off EBay and put this in the socket. Check the loco still runs on DC with this in place. Now take out the DC header and replace it with the decoder checking it is the right way round. Keep the DC header so that if you ever sell the loco, you can take out the decoder and put the DC header in to put it back to DC. Surprisingly DCC ready rather than DCC fitted are more popular on EBAY, plus you can use the decoder on another model.

Hope that helps.

[96RAF]

@colin

Good advice but R7274 is a 4-pin decoder, which the OP apparently already has.

[ColinB]

Oh sorry 96RAF, I didn't realise that, I must admit the only Hornby decoders I have are the 8 pin type. I have got to admit my experience with Hornby 4-pin decoders is not good and I think it was you that mentioned that there were a lot of faults with them initially. I must admit I converted all my Hornby 4 pin sockets to 6 pin as it gives a wider choice of decoders. Surprisingly the 6 pin socket has a smaller footprint than the 4 pin. I think when I last looked the Hornby 4 pin decoder was a lot more expensive than the 8 pin and even a 6 pin Zimo.

[Fishmanoz]

Makes sense, standard railroad 08 is 4-pin, at least mine is.

Also see full answer from me in the other thread with the 8-pin/6-pin title.