I'm finally getting around to replacing bulbs with LEDs on some engines. Anything using an older model Digitrax decoder won't light (mostly DH150K type decoders in Kato locos). Is there anything special I need to do to get the LEDs to work?
Larry
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What model and make loco's are you working with?
Did you use a resistor in series with each LED? If so did you try swapping the polarity of the LED's?
Springfield PA
Anode gets connected to the blue wire. Cathode to the colored function wire. (White, yellow, etc.) Resistor can be in series on either lead.
Martin Myers
Thanks for the responses, but I did not ask my question correctly. I've done over 100 locos with LEDs so that is not a problem. It is the older Digitrax decoders. There is a statement on their instructions about cutting a trace if you are using LEDs, but the diagram does not match up to what the decoder looks like. Has anyone on here hooked up LEDs to an OLD Digitrax decoder (150K series decoder) and was there anything special that needs to be done.
Easiest thing to do would be to leave the traces alone and install a resistor and LED as you normally would. The traces span a pad to solderon a surface moutn resistor for each LED such that for the Kato locos that came with LEDs at the time, you could just solder the LEDs to the end of the decoder with no extra parts. Of course this ignores the fact that it is MUCH easier to solder a normal leaded resistor than to do a surface mount. Either way will work, but do only one, either cut the traces and add the SMT resistor (they came with the decoder) or just leace it alone and install like any other decoder.
--Randy
Modeling the Reading Railroad in the 1950's
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