wiring change on observation rear light

wb47OGR Forum Member DIGITAL SUBSCRIBER

I picked up a nice set of 18 inch Golden State passenger cars. I am not in the process of converting lighting to LEDs using GRJ's kit from Hennings Trains. Easy conversion, except, the observation car on the rear has a rear light. These cars are the K Line aluminum cars with streamlighting. The rear light is attached to the lighting board and it looks like after going through a resistor or a ?. There are 4 of these, I cannot read the lettering on them. I was thinking that I could just cut up the board and wire it to the track power feed, but when I tested that theory with my test transformer, anything over 12 volts caused the light to be very bright and the internal breaker in the transformer would kick out. So, has anyone redone these cars and are there any suggestions. The light is inside a red plastic holder and is hot glued to the car so not easily accessible but it could be. I am wondering if the light can be wired to the new board somehow if it is already and led which I think it is not. So maybe replace the light with what size bulb and then how to wire it in? I attach pictures. Any help will be greatly appreciated. (note, the wires from the light attach to the board on the reverse side below the 4 "resisters", not what the pic looks like.) Bert

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2/24/196:29 PM

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cjackOGR Forum Member DIGITAL SUBSCRIBER

Looks like it’s in series with the rest of the bulbs. Power up the whole board and measure the voltage across the rear light. It’s probably just a couple volts.

2/24/197:31 PM

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John HOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Hard to believe that a bulb would overload a transformer. What size transformer?

2/24/197:49 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Here's how I add LED's to my strips, this is a RK observation car. I just add the three LED's in series and then adjust a series resistor for the correct intensity. These are lighting the two side markers on the roof as well as the rear facing taillight, see circled points.

I'd just replace the bulb with an LED, and I'd start with a 2K series resistor. If that's too bright, increase the value, if not bright enough, decrease the value. For a single LED, I usually end up with between 1500 and 2200 ohms.

2/24/198:37 PM

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wb47OGR Forum Member DIGITAL SUBSCRIBER

GRJ, thanks for the help and diagram, it looks like you have wired the white wire from the light to your strip, the black goes to where? Where are the resistors added in? What size bulb do you like? thanks again Bert

2/25/192:11 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

The solder points on the strips come directly down the sides, so the positive side is on one edge and the negative side is on the other edge. You can see the black wire going out of view on the top, the resistor is just out of view.

The resistor is a 1/8W or larger, it doesn't dissipate much power. The LED and the resistor are wired in series, and it doesn't matter which leg the resistor is in, same effect anywhere in the circuit. I use common 20ma LED's in a variety of styles and colors. They're all generic stuff that I buy in quantity.

You can see on the strip the negative connections are on the top, the positive ones on the bottom. I never noticed before that I didn't include quite enough of the car in the pictures to see the negative connection, it just goes to one of the solder points on the strip.