I modified my bachmann 2-6-0 so the headlight was mounted on the boiler face so I needed to put in a new led, so I took out the old led and lighting board the solderd in a smd led and a 1/4 watt 1000omz resistor. When put it on the track to test it seemed to work perfectly, the light would turn on and off however this only lasted for around 5 seconds then there was a puff of smoke and no more light. I think the wires to the light had shorted, no big deal I figured and solderled in a new led this time taking the time to insulate better. Now when I put the loco on the track the light is on whenever the locomotive has power and does not respond to the function key But ever thing else works as it did before including the reverse light have I partially fried my decoder?
Hello,
The late Randy Rinker used to be quite the expert on diagnosing decoders. Since most are designed with a negative "sink" (electronic switch that can be closed) for function outputs, he has mentioned several occasions where a quick short would disable (ground) the output of that particular function.
A 1KΩ should have been sufficient to keep the LED from frying so you may have had one of the lighting outputs momentarily touch one of the motor leads or track pickup wires.
Depending on the decoder you might get away with using one of the other lighting function outputs for the headlight.
Good Luck, Ed
Reset decoder to factory specs once short is cleared, then you will know if decoder is fried as far as motor, the short may have just jumbled things or it could have fried.
One of my steam engines "blew" the front lighting function of the sound decoder. I ended up connecting the light directly to the wheel power-pickups, temporarily (or not!). These sound decoders are not cheap. I never thought of using the other lighting functions as a power source... I might try that.
Simon