Bachmann Online Forum

Discussion Boards => HO => Topic started by: baldwinmikado on October 30, 2012, 08:30:09 PM

Title: DCC 2-8-4
Post by: baldwinmikado on October 30, 2012, 08:30:09 PM
Ok so i purchased a brand new dcc equipped 2-8-4 locomotive from model show. I get it home and run it and i noticed that the headlights are orange or amber in color. I first noticed this in my dcc 0-6-0, but thought that that was normal as it was my first dcc loco. even after doing some disassembly, the actual lights are this color. I've searched allover and have not been able to find my answer. So, maybe you guys can help. Why does bachmann use these orange or amber colored headlights?
Title: Re: DCC 2-8-4
Post by: Doneldon on October 30, 2012, 09:38:22 PM
bm-

Steam locomotives, especially the ones prior to the 1940s or so, were either oil/kerosene, gas (only a few) or a very yellow
incandescent. Today's bright LEDs are not only bright; they are also rather bluish. The somewhat amber color of Bachmann's
lights more closely resembles the color of the prototype lights.

                                                                                                -- D
Title: Re: DCC 2-8-4
Post by: baldwinmikado on October 31, 2012, 08:37:05 PM
ok well thanks, but i still am confused with them. the light i understand now, but the brightness is confusing to me. There are 2 leds in the front (one for headlight and one for mars light) and 1 led in the tender. the tender light is brighter then the front head lights. can anyone tell me why and/or how to fix and does anyone know how if possible to make the mars light flash with out replacing the standard bachmann dcc chip/
Title: Re: DCC 2-8-4
Post by: richg on October 31, 2012, 10:14:24 PM
Right now, I guesstimate the resistance for the LED in the headlight is on the high side. Many use a 1k resistor which allows about 9 ma. Most LED's for model railroading are 20 ma max. I have seen as much as 2k in Bachmann locos. The loco diagram shows the LED right in the headlight fixture.
A 750 ohm would allow a little brighter LED. About 15 ma. I did a bunch of measurements with my meters and a 12.5 DC voltage.
I do not have this loco, though.  I have seen that with some of the Bachmann with DCC.
The LED resistors are on the PC board that the decoder plugs into. The chips are on the decoder, by the way.
You have to hard wire a decoder using a 1k resistor for each LED or adjust the resistance on the PC board if you can work at what I call the component level.
Some will suggest a different LED.

Dig out your multimeter and do some measuring. That is how I found out what some of the PC boards have.

Rich