I just completed converting my first brass steamer to DCC: An Alco Models NYC M-1 0-10-0 switcher. Along with isolating the motor, I also installed front & rear headlights using 0603 “warm white” SMD LEDs and 34 AWG magnet wire. To make the connections between the locomotive and tender for the rear headlight, I used individual female round headers, which are smaller than regular headers but make a good connection and connect & disconnect easily. I’d like to publicly thank Wayne (doctorwayne) for his tips and recommendations on the latter.
This was one of those projects that you have to think through first before starting it but also be flexible/creative once you get into it. I will definitely replicate what I did and learned on this project when I convert my Alco Models NYC B-11L 0-6-0 switcher to DCC. However, being smaller - I’ll have to modify a few things to make it work - e.g. the placement of the TCS M1P decoder. With the 0-10-0, I could mount it on top of the motor. With the 0-6-0, there’s not enough clearance between the boiler shell and the motor so I’ll have to place the decoder underneath the motor bracket.
This is the first time I’ve used magnet wire for lighting a headlight. Hand-drilling the #79 holes through the brass headlamp and shell took a little time but worked out great. (The biggest challenge was making sure the hole was centered in the headlamp.) And, actually, I found soldering the 34 AWG magnet wire to the 0603 LED much easier than flexible wire because it remained straight and rigid. To deinsulate the magnet wire I used a used#11 X-acto blade to gently scrap the coating off then tinned it with solder.
The other thing I found is that I used much more resistance to tone down the 0603 LEDs than a 3mm - e.g. 10KΩ vs 1KΩ. I
Congratulations on your successful brass engine decoder installation!
I agree that using higher value resistors for steam era headlights is a great idea. Using a 20k resistor would work very nicely based on my (limited) experience with LEDs. I used 30k resistors to get a nice glow reminiscent of early 20th century electric lamps for the interior lights in my McKeen Motor Car.
I too run higher resistance with my LEDs. I rarely run them over a couple of ma. Much closer to incandescent lighting. The warm white 603s and 1206 LEDs still look bright at 2ma.
I use wide angle dispersion 3mm warm white LEDs in my passenger cars, most well under 1ma each. 6 to 8 wide angle LEDs spaced at 1” gives uniform well lit interiors.
Total current for this car 2ma at 4 volts, 4 table lamps and 6 over head wide angle LEDs.
I use the tiny round header connectors in all my passenger cars and a 2K trim pot to adjust the lighting level between 2ma and 4ma.
I still use #36 Litz wire for my micro LEDs, I’m to shaky to install magnet wire without dinging the paint insulation. On occasion I even ding the Teflon insulation on the Litz wire. The tiny wire doesn’t last long under a short. They let off smoke and I haven’t been successful putting the smoke back in the wire, I replace the chard wire.
I bought some ⅛ watt at 2.5KΩ gaps from 1KΩ to 36K specifically for the micro LEDs, the smaller size gets them into tighter places. A 10KΩ resistor in series with a warm white LED draws a whopping .008 watts.
Planning is paramount to a successful install. I have done 5 for myself and several members of my former club totaling around 20. Most have been sound and a few non sound. Some with can motors and a good portion with modified open frame motors.
Most of my installations have been in the tender. I use the TCS 6 wire JST connector from locomotive to tender. I have one 0-6-0 that has a micro sound decoder under the motor because the speaker took up all the room in the tender.
I would love to see what you have done for the connection between locomotive and tender.
Thanks for the kind words. Pete, I would like to eventually paint it but I wanted to see whether it was worth converting to DCC first.
There was definitely a learning curve since it incorporated some new installation techniques and materials I had not used before. It is gratifying to see it come together and work properly.
Your workmanship is impeccable! The socket installations look like they came from the factory that way. You got the positions of the LEDs just right too.
Those small, round female connectors work quite well and make connecting & disconnecting a breeze. I also used them as connects/disconnects for the headlight wiring inside the tender and boiler so that I could remove the shells entirely, if I needed to. Otherwise, they would all be tethered to the chassis.
I used the socket end of the connector to attach the resistors. The twin resistors give the connector a nice uniform appearance and feel:
The biggest challenge with the header strips is breaking them apart evenly. I use a #11 X-acto blade to do that then clean the cut up with the blade or a file. There just isn’t much of a buffer inbetween should your blade veer slightly while cutting downward.
I’ve found that making the cut in stages, alternately from both sides, usually yields a nice clean result, and less chance of the severed portion flying off to wherever that sort of stuff goes.
I tried that approach as well, Wayne. It helped some but sometimes the joint would still splinter and leave a gapping hole exposing the connnector socket. I might have been using a duller blade at the time so I’ll try that method again using a fresh blade.
I long ago gave up on getting good clean sets of header pins. I buy then in large quantities, in strips of 50 or so, big packs - and figure the one at the end of a section when I snap them off is going to be a wasted one. At probably less than 1 cent a pin, I don’t worry about it. I’ve tried cutting, even sawing with a razor saw. 2 pair of needlenose, bend and snap - good enough. If I need a longer strip, like say 16 or so for something, I dispense with the needle nose and just snap it off.
Would there be any advantage to making a ‘hot knife’ with a #1 or #11 X-acto blade in a temperature-controlled soldering-iron handpiece, and then experimenting with one of those spot IR thermometers to figure out the temperature at the ‘cutting edge’ on the part of the blade that gives the best action? Then use a guide like that on a chop saw to hold the blade vertical as ‘the tool does the work’ just a few degrees shy of the material’s melting point?
Thanks for that tip, Henry. It has increased the amount of keepers but I still get the occasional dropouts.
I’ve found that you really have to make sure, when scoring, your score line is parallel to the groove between sockets. Even a slight angle will increase the chance of exposing the embedded socket of the header.
