Help replacing headlight in Atlas YB RS-1

[tstage]

Stix,

I've done something similar with 5/32" OD styrene tubing.  I cut a piece 1/2" long and drill out 1/2 the length with the #32 drill bit.  Once the tubing is glued in place, I paint the tubing black (to reduce bleed-through) and press-fit the 3mm LED inside the tubing.  I used this method to add rear headlights in the cab of an old and a new Walthers SW1 switcher:

Tom

[wjstix]

I generally take cut a piece of 1/8" metal tubing about 1/2" long and glue that in place where I want the LED or lightbulb to go. Then I wire up the bulb and slide it into the tube. That way, the light is better focused, and if I need to replace the bulb, I don't need to unglue anything.

[tstage]

Matt,

I will add an alternate idea to Dave's suggestion above in regards to affixing or mounting LEDs.  While LEDs have much longer life spans than incandescents, they can and do burn out and epoxying them in place makes them VERY difficult (if not impossible) to remove. 

When it comes to lighting, I would recommend Testors Clear Parts Cement (PN 3515 or 281217) over any epoxy. 

It gives you working time to position the LED, dries clear, holds very well, and remains flexible once cured.  And should you need to replace your LED(s) for any reason, they can be peeled off with steady pressure.

If you plan to ditch the light bars and mounting the LEDs directly to the headlight lenses, use a #32 drill bit and drill them by hand with a pin vise.  A 3mm LED bulb generally has an OD of 0.113".  A #32 drill bit will give you a 0.116" OD hole, which is a press fit for the 3mm LED.  Therefore, no adhesive is needed to mount the LED to the headlight lens.  Should the LED need replacing, a firm twist will loosen it from the hole.  Should you still prefer an adhesive, I would again use the Testors Clear Parts Cement but a tiny amount.

If you plan to keep the light bars, I would agree with Stix and Dave that two LEDs would be recommended, as LEDs are much more directional than incandescents.

Tom

[hon30critter]

Hi Matt,

First, I would strongly suggest using two warm white LEDs instead of just one. You will get much better results.

Second, is this locomotive going to be converted to DCC? If so, I would do that first. That will allow you to set the lights up for directional control.

You have probably figured most of this out already, but let me explain the wiring as it sits. It is very simple. You can see the black leads that come off of the trucks and supply power to the copper bus wires that run from one end of the grey board to the other.  The light bulb leads are positioned under the bus bars to provide power to the bulb. The two copper strips that bend around the grey board supply power to the motor. One of those may be connected directly to the frame with the other one connected to one of the motor brushes (someone can probably confirm this). If you are converting to DCC you will have to re-wire the motor feed. You cannot use a live frame with DCC! If you are not going to convert the locomotive to DCC, then using the prewired LEDs suggested by a previous poster would be the easiest way to go.

There are a couple of options when it comes to getting better light out of the headlights and number boards. As I mentioned, using a single LED is not one of them:

The easiest effective solution would be to cut the light bars off leaving about 1" to 1 1/2" on each end where they go into the headlights. Then drill a suitably sized hole into the ends of the light bars so that the LEDs can fit right inside the light bars instead of just up against them. Use clear epoxy to glue the LEDs into the holes and try to make sure that the entire hole is filled. Then, cover the outsides of the light bars with silver paint, except for the lenses obviously. You want to use enough paint that the light doesn't bleed through so it may require two or three coats. This will have the effect of forming a reflector so that instead of having light bleeding out everywhere, it will be redirected towards the lenses.

The more complex solution would be to eliminate the light bars almost entirely by cutting off the lenses and tossing the light bars into your spare parts box. Then, mount an LED behind each of the headlights and number boards. This will give you brilliant headlights but you might want to install a second resistor (10,000 ohms?) for each of the number boards so they are not as bright. Note that you will want to paint the inside of the shell black around each of the lights or the shell may glow in the dark.

If you are using DCC and you really want to get fancy, you could add in classification lighting using RGB 0608 LEDs. It sounds harder than it actually is.

I will add a couple of final notes regarding the use of epoxy glue. First, get the fastest setting glue that you can, i.e. 90 seconds. Five minute epoxy will take forever to hold the LEDs firmly in place. Second, have the LEDs lit when you are positioning them against a flat surface. The LEDs will want to shift around before the epoxy sets and the slightest misalignment will ruin the effect. Hold them in place for a few minutes even after the epoxy seems to have set. The epoxy can still 'flow' slightly even when it feels firm. I use a separate 12 volt power supply with a suitable resistor to temporarily light the LEDs while I am working with them.

Sorry about the long winded response!

Cheers!!

Dave

[wjstix]

You could try one LED, but most I've seen are directional - they are focused towards the end/top of the bulb, so in this situation the brightest light would be shining sideways.

What I've done on some of these is trim the plastic light tube down to allow room for two bulbs, one each direction.

I'd advise using Evan Designs LEDs, you can get them from Walthers or other places. They are pricier than most LEDs, but come pre-wired with resistors and diodes so you can just connect the two wires to track power and the bulb won't burn out - even on a 14V DCC layout. 

https://www.walthers.com/led-5mm-7-19v-universal-ac-dc-dcc-pkg-5-warm-white-266-u50

[crossthedog]

I'd like to replace the dim old bulb in my yellow-box RS-1 with an LED. Here's the bulb in the middle of the loco's guts.

The bulb sits in the middle, and its beam (or rather dim glow) is transferred to the front and back headlights and number boards via these forked pieces of clear plastic. Regardez ici: 

This setup is different from what the Roco-made F7 had. It was very clear what wires went where in that one. But I'm not sure what's going on here. I don't understand where I would attach the wire ends for an LED (with a resistor, of course). I can see the wires coming out from the bulb, but I don't understand the logic of where they go and why. One seems to just get clamped down under the copper wire running front to back, and the other reaches over the edge but doesn't really go anywhere in particular. The big metal plate doesn't seem to have a negative or positive side.

I'd really like to ditch the forked plastic and mount an LED at each end. Does that look feasible? But I think first I will try to see if a single bright LED will maybe do the job. How would you go about this?

Please remember I'm not electrical very much. I know how to strip wire and I can solder, but amperage and ohmage... no clue. Diagrams drawn on the backs of gas receipts always welcome.

Thanks,

-Matt