HST Dummy Car Wiring

[AndyMac1707817969]

I have just purchased a Hornby R2949 HST in Arriva Trains Cross Country livery second hand. Someone has disconnected the wiring inside the dummy car. Could anyone tell me, with the cab of the loco on the left hand side which of the 3 copper contacts for the cab lights (top, middle, bottom) connects to which tab on the circuit board LED 1, 2, 3 and 4

[2e0dtoeric]

You need to find the service sheet for the dummy car, but when I looked, just, it came up not found!

[AndyMac1707817969]

I have the service sheet but unfortunately none of these show the wiring for any loco

[Fishmanoz]

Are there any clues from a similar arrangement in the power car?

[96RAF]

The three contacts will be positive, forward light and rear light but to find out which is which will require a meter to determine if the positive is actually a common positive or it the lights are common negative as Hornby did have both logics on some locos at different times.

 

You can do much the same thing using a couple of AA batteries to work out which one is front and back and by way of which way round the battery needs to be to make the lights work if it is common positive or negative.

 

The hard part comes trying to work out which contact on the circuit board is which. This can be done to some extent by tracking from the contact to the decoder socket, but the PCB tracks may be less than obvious. Some contacts can be excluded straight away as they may be marked M+ - or TL/TR.

 

Using the meter again to find continuity twixt each terminal and the decoder socket pins is the easiest way.

 

Another option is as Fishy said use the other car for guidance and to either rule out or rule in a connection. Remeber on the opposite end car the front/back lighting logic is reversed.

Rob