Model Railroading > Surface-mount LEDs in pilot-face ditch lights?

As long as I have my entire locomotive roster apart for conversion to Loksound, I decided that now is the time to finally get over my fear of adding ditch lights.  I recently ordered enough surface-mount LEDs for the task, but forgot at the time I placed my order that about 3/4 of the ditch lights on my prototype units are flush-mounted on the pilot face, as seen in the attached photo showing my standard Detail Associates ditch light fixtures.  

I'm guessing I would have been better off with standard LEDs that I could have slid through a hole drilled in the ditch light and pilot.  However, now that they're here, I'm wondering if I can make the surface-mount style work in that situation.  They are TINY - not much bigger around than HO scale handrails - so I'm debating a couple options:

• Drill a hole through the lights and pilot face, then mount the LEDs on the inside surface of the pilot.
• Drill a hole through the outside edge of the ditch lights and insert the LED from the side, then run the magnet wires back through the pilot.  My locomotives are mostly black, so I believe it'd be easy to hide the external wires for the short distance they'd be visible.

Any other options I should consider?  Any guidance would be greatly appreciated.

Joe Atkinson
Council Bluffs, IA
www.iaisrailfans.org/../Sub4WestEnd

---

Joe,
           If it were me I would drill a hole 'through' the light fitting & pilot and install from the rear of the pilot, put MV lens in the ditch lights and you should be done.   I'd use a "goo" type glue in case you want to get the LED out though I tend to think you would end up destroying the LED in the process, you could also use a 'gel' type ACC glue for a permanent fixing.         Just my thoughts.

Malcolm
New Zealand.
 

Similar to what Malcolm said, I drill a small hole (#76-ish) through the pilot for the LED magnet wires (aim to the centerline of the engine and you will pop out inside the shell and no one will ever see the magnet wire), pull the LED snug to pilot, then drill out the ditch light housing and mount it over the LED with CA.  I am 50/50 on mounting a lens on the ditch light housing.  3 foot rule applies for me.  I can't see the lens, so I don't do it now.  

Cooper



Edited 3 time(s). Last edit at 09/24/16 20:06 by SOU3921.

---

---

A clear MV lens will probably turn yellow over time.

Victor A. Baird
http://www.erstwhilepublications.com

drill 2 holes #79 or #80 side by side in the pilot face and put one wire through one and one the other. Then the led can`t fall through and will sit more flat against the pilot face.
then the housing can be put in place around the led. I mounted headlights on my GE`s that way

tom



Edited 1 time(s). Last edit at 09/25/16 03:12 by globalethanol.

---

---

Hi Joe.

I have done a few models exactly like you are planning, pilot mounted ditch lights using SMD LEDs and magnet wire.

First I drilled the ditch light casting a bit deeper with a large bit, I think 1/16". I drill until I am starting to drill into the pilot itself. Sometimes I drill one #76 hole through the pilot in the center of the ditch light casting but usually I will do like Tom mentioned and drill two #79 holes instead, one for each wire. Next I run the magnet wire through the holes into the shell, put a dab of Microscale Kristal Klear on the back of the LED, and slide it into place. Once the Kristal Klear is dry I glue on Details West 341 lenses again using Kristal Klear. I use the DW341 lenses all the time now, any MV Lenses I used in the last have turned yellow so they are banned from my workbench.

I attached a couple of pictures from my MRH article that may help.

Andrew C



Edited 1 time(s). Last edit at 09/25/16 05:39 by andrewcastle.

---

---

---

Thank you all very much for your help!  I don't know why it didn't occur to me earlier that I could still mount the LEDs inside a pre-existing ditch light casting, but that's definitely the way to go.  I guess I'm still adjusting to just how tiny they are.  I originally installed MV gems in them after giving up on ditch lights following my first attempt, but still have a bunch of clear lenses from the DA ditch light castings I'll use now.  I should have mentioned yesterday that I'd already installed the castings, as that kind of ruled out any options that involved fitting them over an already-installed LED.

By the way, the Ebay seller for the pre-wired LEDs I bought also has a number of how-to videos posted on YouTube (e.g. search for "02.15.15 MONSTER LEDs").  In that one, he recommends Aleene's clear tacky glue for LED installation, as it dries clear and is water-soluable for easy repositioning later.  I found it at Hobby Lobby.

Am I understanding correctly that I don't need resistors on either the headlights or ditch lights when using Loksound decoders?

Thank you all again!  After honking up my first ditch light attempt with bulbs about 10 years ago, I've been fearing this process all this time, but now I'm looking forward to it.

Joe Atkinson
Council Bluffs, IA
www.iaisrailfans.org/../Sub4WestEnd

Joe,

The Aleene's Tacky Glue should work fine, I think it is very similar to the Microscale Kristal Klear that I use.

Can't help you with the Loksound hookup as I am decoders with a 12V output. For 12V I usually wire the LEDs in series with a 4.7K Ohm resistor. I read somewhere that you are better off hooking up LEDs in parallel each with their own resistor but hooking them up in series works for me.

Andrew C

If you are installing the LOK Sound select direct (ie the board type) decoder you do NOT need resistors for the LED's

-Trevor

You DO NOT need any kind of resistor on Loksound boards.  Your common wire goes to "+UB" on the board and you are good to go with LEDs.  I am currently finishing the last unit of fleet swapping over to Loksound and LEDs.  It's almost taken two years, but it's been well worth it in my opinion.

Cooper

SOU3921 Wrote:
> You DO NOT need any kind of resistor on Loksound
> boards.  Your common wire goes to "+UB" on the
> board and you are good to go with LEDs.

Thanks Cooper.  A friend of mine tells me that that's only true of the Select Directs, as Trevor implied above.  I plan to purchase only Select Directs from here on out, but the first 7 decoders I've installed were Selects with the 8-pin plug that I took in trade from a friend, so it's sounding like I need resistors for them.  I'm pretty awful at anything resembling electronics, so could someone please point me to "LED and Resistor Wiring for Dummies", or an equivalent, online?  A few of my questions:

• Does the direction of the resistor matter?
• Which ditchlight wire do I put the resistor on?
• Can anyone familiar with Loksound Select 8-pin decoders suggest where I'd connect the LEDs?
• Any other guidance?

The LED kits I bought on Ebay include 750ohm resistors, and the seller said he uses one of those for both ditch lights in his own models.  Since he sent me 72 of them, I'd like to use those if at all possible.  Any guidance would be gratefully received!  Thank you all very much.

>I am currently finishing the last unit of fleet swapping over to Loksound and LEDs.  It's almost
> taken two years, but it's been well worth it in my opinion.

Same boat here Cooper.  How many units have you converted in that time?  I'm doing 35...and hoping they don't take two years! :-)

Joe Atkinson
Council Bluffs, IA
www.iaisrailfans.org/../Sub4WestEnd

iaisfan Wrote:
-------------------------------------------------------

• Does the direction of the resistor matter?
  >Joe if you mean does a resistor have polarity.....no it doesn't matter resistors don't have polarity
• Which ditchlight wire do I put the resistor
• > on?
  > I have heard it doesn't matter, while I've also heard always on the function wire which is the negative side of the circuit, I always have my resistors on the negative side and not on the common which is the positive side
• Can anyone familiar with Loksound Select 8-pin
  > decoders suggest where I'd connect the LEDs?
  >Sorry no experience with the lok sound eight pin, but I would assume somewhere on your loco's circuit board.
• Any other guidance?
  >Check out Mr. DCC University website, he has a section on LED usage

Thank you Jeff!

Joe Atkinson
Council Bluffs, IA
www.iaisrailfans.org/../Sub4WestEnd