Multiple LEDs on FX-DO

Joó Ferenc

I have a couple of the Titan FX-DO decoders designed for O scale but am using them in two G scale SD45 locos as the 8 Amp peak (4 Amp continuous) is plenty enough to drive them. 

However, that's just it, as I am having trouble configuring the lights, so I am driving without the lights.

The FX-DO has two 8-pin connectors, each of which have 6 function ports, a ground and a 5 Volt + pin.

The Titan is great as has separate step lights and truck light outputs. However, usually you need to add 4 LEDs for both, or in the case of step lights, you have a few along the catwalk around the loco. In my case, I added two more step lights to where there are steps at the cab doors, so I would need 9 LEDs to be driven from the same port.

Sadly, 5 Volts are not even enough to drive two LEDs for say tail lights and Kelly suggested to use an opto isolator and a separate device for power, to drive any consumer that need a higher voltage or power.

I guess it is not wise to connect the LEDs to the track + port as then the function ports will receive track voltage which in my case is 24 Volts, and that will likely damage the decoder.

Now I know that there are some decoder manufacturers who have 5V+, 10V+ and track voltage + on their decoder (like Zimo and I think ESU, too) but I presume this is not the case with the Titan FX-DO. Would anyone have any knowledge on this, please?

Any suggestions on how to connect say 9 step lights to the FX-DO? Obviously I furst need to split them in two circuits as 24 Volts wouldn't be enough for 9 LEDs if they all need like 3 Volts each.


Best regards,

Ferenc Joó
Correspondent for Hungary
TREU - Today's Railways Europe
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