Repairing Hornby 4-pin loco to tender electrical plug

[Challenger_2MBT]

Hello,

 

I am hoping I can get some advise on repairing the 4-pin loco to tender electrical plug on the newer Hornby Schools class locomotive. Is there a wiring diagram/schematic print to reference available? I've ordered the replacement parts as well as the tool to facilitate the insertion and removal of the plug.

Thank you. 

[RAF96]

Not sure if you want to fettle the plug or the socket wiring so I'll describe both.

Assuming initially decoder socket is in tender.

 

With the tender facing forwards this is the wiring configuration.

Left hand outer wire is LH tender wheel pickup

Left inner wire is Motor -ve.

Right inner wire is Motor +ve

Right hand outer wire is RH tender wheel pickups.

 

Looking at the loco plug these wires will match the socket except wheel pickups will be from loco.

 

If 8 pin decoder socket is in the tender then

pin 1  (marked with a triangle) is Motor +ve,

far opposite corner pin 5 is Motor -ve

and the other 2 corners are the wheel pickups i.e.

pin 8 - RH adjacent corner to pin 1

and

pin 4  - LH adjacent corner to pin 5  according to NMRA standards.

 

If decoder socket is in the loco then there will only be 2 wires from tender to loco - the pickups which should be easy to find which is left and which is right.

 

The important bit is to ensure loco left and tender left pickups match else you will have a short.

 

You will probably find all these wires are black not helping much to sort out the tangle.

Edited February 19, 2015 by RAFHAAA96

[Challenger_2MBT]

Not sure if you want to fettle the plug or the socket wiring so I'll describe both.

Assuming initially decoder socket is in tender.

 

With the tender facing forwards this is the wiring configuration.

Left hand outer wire is LH tender wheel pickup

Left inner wire is Motor -ve.

Right inner wire is Motor +ve

Right hand outer wire is RH tender wheel pickups.

 

Looking at the loco plug these wires will match the socket except wheel pickups will be from loco.

 

If 8 pin decoder socket is in the tender then

pin 1  (marked with a triangle) is Motor +ve,

far opposite corner pin 5 is Motor -ve

and the other 2 corners are the wheel pickups i.e.

pin 8 - RH adjacent corner to pin 1

and

pin 4  - LH adjacent corner to pin 5  according to NMRA standards.

 

If decoder socket is in the loco then there will only be 2 wires from tender to loco - the pickups which should be easy to find which is left and which is right.

 

The important bit is to ensure loco left and tender left pickups match else you will have a short.

 

You will probably find all these wires are black not helping much to sort out the tangle.

Many thanks for your help. Just waiting on the replacement parts to affect the repair. Hopefully all goes well.

[Tim123]

On 23/04/2021 at 15:23, cbrooks122000 said:

Sorry to resurrect this thread but I am repairing an old City Of Sheffield Duchess. This has a 21 pin DCC socket in the tender with I assume a LokSound decoder. Looking at the web it was supplied with this. Needless to say there were lots of issues with the loco, but I noticed that the Loco/Tender connector is wired different. The two inner wires pins 2 and 3 go to pickups, whereas pins 1 and 4 go to motor. This is the opposite to my current Hornby locos and the ones where I have added the loco/tender connection. Did Hornby originally wire it this way, because it means if you connect the tender to a more modern loco for testing you would blow up the decoder.

 

I've seen this before, basically it depends upon which factory assembled the loco. Hornby have used various manufacturers in China, and they may not have followed the instructions on wiring, assuming that such instructions were supplied. You just need to make sure that the loco and tender are kept together. 

 

Back in the days when locos started to be loco drive again but still relied on the brass pin and two upward facing contacts to collect power from the tender I was given two DC powered Merchant Navy locos to look at. Both were shorting out when the tenders where attached. No prizes for guessing what had happened 

[Right Away]

Might this be of help?

Having had cause to trace the plug/socket wiring myself, I roughly sketched out the following in a notebook ...

Hope it is reasonably self-explanatory.

 

[RFS]

I have a problem with a Hornby King Arthur where one wire has come loose from the plug. I can't see how to easily repair this, so can anyone advise how this is done?

 

Thanks

[RAF96]

1 hour ago, RFS said:

I have a problem with a Hornby King Arthur where one wire has come loose from the plug. I can't see how to easily repair this, so can anyone advise how this is done?

 

Thanks

 

It is not easy to re-insert a wire to either a plug or socket and the simplest way is to replace the whole plug or socket as they are readily available as spares from the usual suspects.

Check the service sheet though as there are two socket variants - one is axial and the other the more usual right angled one.

[Andy Russell]

I have a first release Hornby Clan locomotive and this plug is a pain in the posterior which as I only run DC control do not need.

 

I am going to take off the Loco body and connect the pick-up wires direct to the motor. I will put the plug inside the body covered with heat shrink sleeveing  to avoid any contact with anything inside body. Tender pick-ups in my locos are not required as the all run without them. So goodbye plug and far easier to hitch up loco and tender

[Mallard60022]

Just been linked to this original post having got exactly this Schools problem. Absolutely gold information all, especially the wire positions; many thanks indeed.

P