Re-using factory light board

[texasperry]

Folks,

I am trying my hand at my fisrt Non drop in decoder sound install.

I have an N scale MT FT. using ESU deocder.

I would like to retain the factory board and use the LED already mounted. Maybe I am making more work for myself. It just seems like a good way to hold the LED in place and not have to assemble a LED and resistor. Things are tight enough in an N scale loco.

I want to cut the trace and wire the decoder light function to the factory board.  I am not sure where to cut the trace. I see what looks like a surface mount Resistor in line with the + to the LED,  ahead of that is what looks like another resistor, that crosses the + and - at the LED. It is black with a silver band.

Can anyone advise me?

Thanks

Perry

[woodone]

I just finished doing one like you have. I will take a photo of the board and get back to you.

 

[BigDaddy]

texasperry

I want to cut the trace and wire the decoder light function to the factory board. I am not sure where to cut the trace.

If you do that, won't you give up DCC control of the lights?

[rrinker]

 The black with silver band component across the LED is most certainly a diode, which is basically there to protect the LED when the loco runs in reverse. All you need to connect a decoder is the LED and a resistor - the resistor already there is probably too low a value though. It has to allow the LED to light across a wide range of voltage for DC operation. DCC is going to put a constant 12V or more on the LED, so it will either be running over current, or right near the current limit and thus extremely bright, if connected to DCC.

                                   --Randy

 

[texasperry]

Is it better to solder direct to the truck for track pick up or to the brass contact strip. 

It seems re-using the "factroy Light board for this is going to be more work. 

I have abandoned that idea. but now need advice on where to solder Pick up wires

Thanks.