Farish Class 40 with 18 pin socket lights not working

[Mogga]

So I recently bought the Farish 40 with the next 18 pin socket.

 

I installed the Bachman decoder that I purchased at the same time. The loco runs well and I really like the model. I do however have a problem with the lights. The front/forward lights only work at one end. 
 

I see there is a bit of content related to this issue on here but as someone relatively new to DCC I can’t understand a lot of it. Is anyone able to explain what is going on in very basic terms? 

Edited January 15, 2022 by Mogga
Clarification

[grriff]

I understand from your post that one set of front lights is working but those at the other end are not. I presume both sets of rear lights are working. Therefore the problem is not likely to be with the DCC chip although it is possible one of the CV variables is incorrect. Before we get into that complexity I would check the wiring from the decoder to the lights. 

[Mogga]

I’m struggling to get my head round cvs. What is the difference between a function and a cv and how do they interact? 

[Nigelcliffe]

Back at basics:   What do the instructions with the loco say ?   

 

I'd assume the lights are wired to the normal default function outputs.   So, not working at one end might be one of: 

 

• Poor contacts internally.   If removing and refitting decoder doesn't fix it, the loco is faulty.  If not within your skills to diagnose further, contact retailer for replacement/refund as it is faulty.  
• Operator error on DCC handset.   Knowing how Farish wired their 31, and guessing the 40 might be similar (can't find any instructions on Bachmann-Farish website), make sure that only F0 (lights) is on, and no other function keys are on.    The way Farish set up the wiring on the 31, with an "out of the box" decoder, the lights worked on F0 (lights), and the F1 and F2 keys would turn-off the lights at one end or the other.  

 

 

CV's, functions.   

Functions usually refer to the output wires (or contact pins) on a decoder.  Individual lighting outputs are connected to each function.    Function keys are the F-numbered keys on a DCC handset.   

CV's are "configuration variables" - they are the settings inside a decoder to setup (program) what a decoder does. They include its address (the loco number it responds to), and control what output is controlled by which key, how the motor behaves (speed, acceleration, and fine tuning of motor performance) and numerous other features. There are typically hundreds of CVs in a modern decoder.     To make something "just work" you shouldn't need to touch them, other than the loco address.   

 

 

-  Nigel

 

[grriff]

A CV determines what the loco will do in certain circumstances. For example a value between 1 and 255 in CV5 will determine the maximum speed. A function will carry out an action depending on what values are in the CV related to the function. For example a value of 8 in CV 33 and 16 in CV 34 should result in function 0 turning the front and rear lights on and off - that's for the Bachmann EM1 decoder. Your decoder should have a table showing what each function does. 

Edited January 15, 2022 by grriff
Added ref to CV5

[Mogga]

Thanks for the input guys. Very informative 

[ahellary]

hi i have a factory sound fitted one and i noticed that one ends cab lighting wasnt working ...what i needed to so was just tweek the contacts to connect better