Front/Read Lighting

[HaroldA]

I have an IHC Consolidation in which I had installed a Digitrax DH123 which was working great until it was fried a few days ago. I removed the bad decoder along with the harness and installed a new DH123 today. The direction of travel and motor work fine, however, I cannot get either front or rear lights to work. I am using the blue wire as the feed with the white wire going to the front and the yellow going to the rear. They are good bulbs and worked with the old DH123. Any suggestions?

[richg1998]

Do a decoder reset. If bulbs still do not come on, take you multimeter and on the DC scale you should read about 12 volts DC with the light selected on your controller between the yellow and blue and white and blue.

You say the bulbs are good so I figure you checked out the bulbs with an ohm meter.

Rich

[HaroldA]

I did the reset and still no lights. What baffles me is this is the same type of decoder wired the same way as before. The lights worked then but not now. Again, the bulbs are good and functioned perfectly with the now fried decoder.

[rrinker]

 Is there a short such as worn through insulation on one of the wires going either to the headlight (most likely) or the tender? This may be what fried the first decoder.

                   --Randy

[richg1998]

Usually what fries some decoders is a motor wire coming in contact with either the right or left rail pickups. Many define a fried decoder as there is visual damage to the decoder.

I have had a decoder go bad but I did not define it as fried as the sound and functions worked but no motor drive. A chip on the decoder board was bad from a over current condition to the motor.

Rich

[HaroldA]

rrinker

 Is there a short such as worn through insulation on one of the wires going either to the headlight (most likely) or the tender? This may be what fried the first decoder.

                   --Randy

I have replaced all the wires going to the headlight as well. I thought about the possibility of a short since the two wires are tight against the boiler weight. Like I said, both lights work under voltage from a power pack so it would seem a short there would show up. This has me completely stumped since all I did was replace the decoder wire for wire. Tomorrow I am going to buy a new decoder and see if that makes a difference. I am still open to any suggestion.

[richg1998]

A way to check the decoder is to use your voltmeter and look for 12 volts or so at the decoder leads like I mentioned before. If you do not have a meter, get a couple of the below meters. They do just about everything a model railroader would want in a multimeter. I have three of these from Harbor Freight.

http://www.harborfreight.com/7-function-digital-multimeter-90899.html

Get a set of double clip leads if you are going to continue working at what I call the component level.

http://www.harborfreight.com/18-inch-low-voltage-multi-colored-test-leads-66717.html

Rich

[HaroldA]

rrinker

 Is there a short such as worn through insulation on one of the wires going either to the headlight (most likely) or the tender? This may be what fried the first decoder.

                   --Randy

I have replaced all the wires going to the headlight as well. I thought about the possibility of a short since the two wires are tight against the boiler weight. Like I said, both lights work under voltage from a power pack so it would seem a short there would show up. This has me completely stumped since all I did was replace the decoder wire for wire. Tomorrow I am going to buy a new decoder and see if that makes a difference. I am still open to any suggestion.

[HaroldA]

In the meantime I pulled another DH123 decoder from another engine, installed it the Consolidation and reset it. When I connected the yellow and blue wire to the rear light it did light and when I connected the same leads to the front light, it also worked. However, when I connected the white and blue wires to the rear light, it did not light and neither the front. I am going to replace the headlight wiring again to see if this makes a difference, but right now I don't have a clue. I will purchase the meters you recommended but after reading this, does anyone out there have any other ideas?

[rrinker]

 Well, there are pretty much only 2 options: either the decoder is not turning on the function (blue is positive, if you check with a meter), or the circuit is not complete to the light bulb. If the bulb is 12V, or has a resistor in the circuit, you cna connect a 9V battery to the wires leading to the bulb (decoder NOT connected unless you want to fry another one). If the bulb and wiring are good, it shoud light up.

And then there is the obvious - have you turned F0 on once the decoder's address was selected?

                                  --Randy

 

[HaroldA]

rrinker

 Well, there are pretty much only 2 options: either the decoder is not turning on the function (blue is positive, if you check with a meter), or the circuit is not complete to the light bulb. If the bulb is 12V, or has a resistor in the circuit, you cna connect a 9V battery to the wires leading to the bulb (decoder NOT connected unless you want to fry another one). If the bulb and wiring are good, it shoud light up.

And then there is the obvious - have you turned F0 on once the decoder's address was selected?

                                  --Randy

 

Randy, I will do the 9V battery thing tomorrow. I can take the leads for both lamps and put them on the rails and both lamps will light. Also, tomorrow I will buy a new decoder since the one I installed was already here. What is puzzling is that I have wired everything the exact way as before but there is this issue. I did find this article - http://tsd.digitrax.com/index.php?q=80 - on the Digitrax site and it refers to CV 40 and 50 - but I interpret this to be for special effects and I know I have never had to program these before. I did turn on F0 which is how I know the rear light worked for the other decoder and not the headlight. This caused me to replace the headlight wiring but I got the same result as before. As a last resort, I can use the decoder that allowed the headlight to work and forget the rear - but again, this is a last resort.

[rrinker]

 Also try setting CV8=8 to reset the decoder. The defualt lighting funtions are simply on/off directional lights, if any of the lighting effect CVs got changed, or as sometimes happens were let in an odd state from testing, it may not work as expected. If you do the CV8=8 reset, it will set the lights back to basic directional lighting.

                  --Randy

 

[HaroldA]

rrinker

 Also try setting CV8=8 to reset the decoder. The defualt lighting funtions are simply on/off directional lights, if any of the lighting effect CVs got changed, or as sometimes happens were let in an odd state from testing, it may not work as expected. If you do the CV8=8 reset, it will set the lights back to basic directional lighting.

                  --Randy

 

I did that as well on both decoders - lights still didn't work as they should - but I will try it again. I know the wiring is correct and the bulbs work so I am suspecting the decoder. There is a guy at my LHS who is the 'resident DCC expert' and I will take everything to him tomorrow to see what he thinks. In the meantime I am going to purchase a new decoder and those meters someone suggested in an earlier post. This has me stumped - I am usually pretty good at figuring things out but this is the proverbial conumdrum - especially when I can get the yellow/blue combination to work but not the white/blue. If you can come up with anything else let me know. If I get it working I will let you know as well.

[Hamltnblue]

Is the headlight definitely a bulb and not an LED?  Also did you check the voltage on the headlight wires without the bulb connected?

 

[HaroldA]

Thanks guys for all the help with this mystery. I did everything you all suggested and still ended up with the same situation. So, I went to my LHS and purchased a new decoder, installed it, and both lights work fine. All I can think of is that both decoders I was trying to use were somewhat defective - if that is possible. All I have to do now is put everything back together, tape off the weight in the tender - which contributed to the original problem - and reprogram everything. I may decide to change out the bulbs for LED's but that will come later.