Has anyone added ditch lights to the BLI Paragon 4 N scale NW-2? I would like to add both front and rear ditchers, but I'm not sure of the best way to attempt this. The DCC board is marked N-500-G. There are no solder pads I can see for additional functions, although there is a very small plug at each end to connect the various wiring. It appears there may be two unused wire slots on the plug, but adding wires to these plugs seems very iffy to me. I could also tap into the front and rear headlight boards, but I cannot find any documentation as to whether the front and rear headlight function outputs can each handle the current load for two additional LEDs (which would need to be wired in parallel with the headlights). I wouldn't be able to separately control the ditchers this way, but at least they would go on/off with the headlights. Steve Troy
https://www.trainboard.com/highball/index.php?threads/some-decoder-comparisons.145664/#post-1237709 Is there enough room to put a very small zimo or esu decoder above the decoder there and use it only for flashing ditch lights? Sumner
Unfortunately, there is no room whatsoever. N scale switchers don't give you much space to work with. Steve Troy
One option, assuming the function outputs are approximately 12 volts, would be to wire the ditch lights in series with the front or rear headlight. You would have to change the resistor (or jumper it and use a separate one), otherwise the lights would be much dimmer. When you wire LEDs in series, they "share" the same current. For example, if you configure them to draw 10 ma, each one will light at 10 ma; however, the total current draw would still only be 10 ma, not 30. Most white LEDs drop around 3.5 volts, so 3 would give you about a 10.5 volt drop, so you could use 3 in series on 12 volts (you would use 1.5 volts to calculate the resistor size: 12- (3 x 3.5) = 1.5). The only real issue I see with this is you cannot adjust each LEDs brightness individually, so, for example, if the ditch lights are to bright you can't dim them without dimming the headlight. Also, if you dim the headlight using the decoder function the ditch lights will dim as well. Not knowing what LEDs Broadway Limited uses, you may even have to replace it when adding the ditch lights to get uniform lighting output.
Here's an update. The Paragon 4 provides 3.5V to each headlight LED. This is good news, since there's really no room to add a resistor. The headlights are surface mount LEDs on miniature circuit boards that have red(+) and black(-) wires soldered to them. I can tap into these solder connections to run wires to the ditch lights, hooking them up in parallel, as 3.5V isn't enough to hook up in series. I temporarily hooked up two additional white LEDs I had lying around to each headlight circuit and they work in tandem with the headlight. BLI has confirmed that won't damage anything. Here's the interesting thing with the Paragon 4 in this particular switcher - when stopped, both front and rear lights are on dim. When moving, the light in the direction of travel goes on high while the opposite light goes out. So, when stopped, the ditch lights will be on dim in both directions, but when moving, only the ditch lights in the direction of travel will be on. I can definitely live with that. The other option is to turn on "Pro mode lighting" (set CV128=1) where F0 will turn on front light/ditch lights and F3 will do the same for the rear lights. F7 will dim the lights. I might try this and see if I like it better. So now to wait until the ditch light castings arrive so I decide which LEDs to order (either nano or pico size). Steve Troy
Sounds like you have things worked out Be sure and post some final picutres at least or hopefully also on the LED install. On the LEDs I bought some 0402's and really like them. I have larger ones also but I'll probably be using these a lot. They are really small but ... ... can also be really bright (above I had 360 ohm resistors with each one on a 5 volt circuit). Running at 3+ volts and no resistor they probably will be brighter. If whatever you end up using are too bright I'd think you could still... ....find a place for resistors. Those above are 1206's (.120-.130"x .060") and you could go even smaller with 0603's (.060" x .030"). Cut the really small wire to or from the LED and solder it to each side of the resistor with a drop of solder and put some Kapton tape on/around it. Sumner
Yes, I will post some photos when I get to work on it. Depending on the size of the ditch light housings, I may have to go smaller than 402s. When I hooked up the 3mm LEDs I had lying around, they were the same brightness as the onboard LEDs (which look like 402s), so I'm hopeful that I won't have to mess with any resistors as space is very, very limited. I can run the wires to the LEDs down through the holes in the frame for the truck pickups (which are wired rather than using wipers). STeve Troy
Just a thought, but if you are settling for the ditch lights to work with the headlights, would it be easier to just run some fiber optics?
Down to 201's (about 3 inches in N scale)? I forgot about those and also forgot that I had bought some. I haven't used them yet not even to just try out. The specs (not sure if they are accurate) claim a forward voltage of 1.8-2.4v. If that is true they might not last too long on 3.5 volts? Good luck and have fun with the project, Sumner
I thought about that, but (1) the bends would be really severe (several sharp 90 degree bends are required) and (2) the fiber optics would have to enter the ditch light housings from the bottom since they are porch-mounted. Steve Troy
I'll have to re-check the actual circuit voltage with a meter, but I don't think it is putting the full 3.5V to the headlight LED. Evans Designs list their NANO and PICO LEDs as 3v. Steve Troy
I checked the voltage to the headlight circuit board, and it's only 2.75v, so the 3v LEDs I plan to use will pose no problem. Steve Troy
Well, it took me a while to complete this project. After giving it much thought, I decided to bite the bullet and replace the Paragon 4 with a Loksound 5 Nano so that (1) I could control the ditch lights independently and (2) so I could get the correct horn for this loco. I also crammed a TCS KA-N1 keep-alive in there. I used Evan Designs "Z" pre-wired LEDs - these are unbelievably small and bright! I bought ditch light housings from CMR products on ebay. When buying "Z" LEDs and these ditch light housings, order TWICE as many as you need as you will probably ruin a few, like I did. They are very fragile. Using a #65 drill to open up the ditch light housing, I was able to glue the LEDs in from behind. Lucky for me, the actual #446 doesn't have blinking ditch lights when the horn sounds, so I was able to wire the ditch lights in series along with a 15K ohm resistor (these little LEDs are extremely bright - even with a 15K ohm resistor, I still had to set the ditch light brightness to 50%). I used the original headlight boards, and a 1.5K ohm resistor worked fine for these. I also removed all the factory wires attached to the various AUX solder pads and used the thinner wires attached to the LEDs to gain a little breathing room. I put the front ditch lights on AUX1 and the rear on AUX5 and disabled all the other AUX outputs so nothing could short out anywhere by accident. I remapped the front ditchers to F5 and the rear to F6 so my NCE throttles can display when they are turned on. This little guy runs and sounds just great, and I'm very happy with how it all turned out. Steve Troy
