IM FT headlights

[TVRR]

I have several A units that no longer have functioning headlights. They are equipped with Digitrax decoders and run fine otherwise. Is it possible to remove the current LED and replace it without doing ugly things to the board?

[tehachapifan]

All the LED's burned out? Isn't that unheard of? are you sure they're just not programmed correctly?

[garethashenden]

My FTs have the headlights connected to the board by a pair of wires. You unsolder them from the original board and then attach them to the decoder. I'd check that they're still connected. If they are it should be straight forward to replace them with new LEDs.

[gbcaboose]

I have the same issue with a pair of FP7's.  I installed the digitrax decoded and soldered the lights to the board and the lights haven't worked since. I'm wondering if the heat produced from re-soldering the light Fried the LED. My soldering skills are sub-par but I don't think they're that bad. Right now the locos are on the "I'll get around to them later" list.

Mike

[peteski]

Mike,  I'm not familiar with that install, but is it possible that the decoder does not have built-in current limiting resistors on the headlight output and connecting the LED directly to the decoder simply burned the LED (due to no resistor in the circuit).  What is the decoder's model number?

[EL3632]

If you (accidentally) have exposed wire touching the frames (very easy to do on these models with drop-in decoders, the wires are short and easy to accidentally hit the frame without realizing it) the LED will blow out. I think I blew 4 out in this way.
You should be able to replace the LED, with nothing more than resoldering the leads on the decoder, but removing the old one will be quite a challenge, they seem stuck in the housing they're in, and I have not tried to remove any for that reason.

[gbcaboose]

Thanks EL3632. Next time I get these out I'll check for that.

Pete, Decoder is Digitrax DN166I2B.

Mike

[peteski]

Thanks EL3632. Next time I get these out I'll check for that.

Pete, Decoder is Digitrax DN166I2B.

Mike

Thanks.  I checked that decoder installation guide and it appears that there is a 1000 ohm resistor on the positive side of all the function pads, so no additional resistors were needed.  If the LEDs stopped working then it is either bad wiring, LED, or even maybe the decoder itself.

[TVRR]

All the LED's burned out? Isn't that unheard of? are you sure they're just not programmed correctly?

The units in question( 3 out of 7) have the LED as part of the board, no soldering done on installation, and worked OK for several years. The boards are cheap enough that I may just replace them but I had thought about snipping the old ones off and replacing with LEDs off the original DC boards I still have. Many thanks for all the info offered guys.

[peteski]

The units in question( 3 out of 7) have the LED as part of the board, no soldering done on installation, and worked OK for several years. The boards are cheap enough that I may just replace them but I had thought about snipping the old ones off and replacing with LEDs off the original DC boards I still have. Many thanks for all the info offered guys.

The LEDs in your installs are soldered directly to the decoder?
Yes, you could snip or unsolder them out of the decoder and install replacement LEDs.  But the question remains: why did they stop working?  LEDs are solid state devices and have extremely long life (pretty much for many decades), so if you have so many no longer working, something unusual is likely happening.

[jagged ben]

I would certainly do a factory reset on the decoder and really make sure it's not a programming issue before I broke out the soldering iron.  There's lots of possible random programming issues, and I've seen my share of decoders forget they're programming.

[TVRR]

I took one apart this AM and found that I was incorrect about how they were installed, there are two wires soldered to the board leading to the LED in the housing. Also found under magnification that the Positive wire was broken at the LED. It's been 15 yrs since the DCC install and I had forgotten a lot it appears. I am going to contact IM Monday and see if the lighting unit (LED, housing, and wiring) are available as replacement parts. 

[RBrodzinsky]

It is a real simple fix to resolder the wire at the LED, or just put a new LED into the housing.  Takes a standard size (T1 3mm, i think), and you can even replace the IM installed orange with a "warm white" LED