I have a locomotive with a 3 volt LED for a headlight. Resistor is 1K ohm. I thought I had it wired correctly, but while the light comes on, I can't turn it off or dim it either using my JMRI or power throttle (DCS50). Blue function wire is soldered to the anode and the resistor and then white wire is soldered to the cathode. I've done a dozen of these before and they all worked correctly, but this has me stumped. Must be my age (now 68). LOL. Any suggestions?
JRP
When something happens with an install, I do a decoder reset. Cycle track power.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Rich, yes. I have done that several times, making sure all CV's were reset to factory. But light still "stays on" when first soldered.
A function that always stays on usually indicated the function output that it's wired to is blown. The blue wire is +, so each of the colored function wires is actually a switch to ground. When the driver fails it often fails shorted, which is like it's permanantly wired to the - side of the circuit, thus the light stays on.
I assume this is an LED since you have a 1K resistor and menthoed the blue wire is connected to the anode. Incandescent bulbs don't have anodes.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
JRP Rich, yes. I have done that several times, making sure all CV's were reset to factory. But light still "stays on" when first soldered.
Ok. I did not see anything about resets in your post.
Looks like Randy must have the answer. I have never had this happen.
I read Randy's note too. So I sent a note to Soundtraxx asking them. I'll let you and Randy know what they say. I hope I don't have to replace the decoder. Not that old and barely used.
SoundTraxx did repair a lightboard decoder for me some years ago maybe under ten dollars as I recall.
Did you make sure to isolate the headlight from the old frame? Many DC locos have a frame which makes up part of the DC circuit. When replacing a DC bulb with a DCC LED, you've got to make sure the LED does not make contact with the old bracket.
Also, what about the reverse light on the same engine. What happens with that when you reverse the engine?
It takes an iron man to play with a toy iron horse.
No, and I did not know that. But the LED was placed just behind the two headlight "holes" in the shell, held down with tape. It was never touching the frame. This unit is a newer Athearn RTR GP35. What I will do is test the light now that I have removed it from the shell temporarily and see if it stays on. I do not have a reverse light on this unit as this is a lead unit for a 4 unit consist. The last GP unit will have a reverse light.
When you say "the light won't go off," are you referring to turning it off with F0, or to putting the engine in reverse so the front headlight goes off?
Have you made any changes to CVs?
While you have the lamp out, give it a test with the Rear side rather than the front side. You should have the front lamp connected to the white and blue wires. Disconnect the white wire and connect the lamp to the yellow wire instead. It should now operate when the engine is running in reverse and be off when it's going forward.
If you find the lamp works properly (other than direction) with the yellow wire, you may have lost the F0F function which controls the white wire. If so, you can simply use the yellow wire and do a bit of function remapping with CVs.