Digitrax LED voltages...

[sizemore]

So I'm finishing up one of 3 of the RDC's (need to get more decoders) and waiting on a rather large check too...and I wanted to know about the LED's that are used. I would like to know what the voltage so that I can find a suitable yellow-glow replacement. Unfortunately the DCC system I want is...waiting on the check. So I have no means of testing. I am assuming it's a 3-4 volt LED based loosely on size and comparison to other available LED's.

What say you, my electronic whiz-bang junkies?

[fieromike]

To keep things really simple, a 1/4 watt, 750 ohm resistor in series with the led will do just fine.

[sizemore]

To keep things really simple, a 1/4 watt, 750 ohm resistor in series with the led will do just fine.

Thats the problem the LED is mounted directly to the board, so it fits properly into a channel in the model to light specific lights -no room for the resistor.

T

[up1950s]

Led voltages go more by color than by size .
http://www.theledlight.com/LED101.html

Put the resister on the board the led fits on , or the feed that the board gets its voltage from . Slit a section of the printed ckt and fit the resister across that gap . Pictures and known voltage points would help folks help you .

If this is DCC can't you program the led voltage ?

[Walkercolt]

99% of "white" LED's will stand 4 volts positive. The 1% are the new super micros Richmond Controls sell. Pull the Kato LED and replace it with a more yellow LED, or easier, color the Kato LED's with an orange "Sharpie" or dip it Tamyia clear orange paint. I used Sharpie's on my Kato "blue laser" headlights, and they still look good after 5 or 6 years. I did about 20 Kato's for a customer at the shop with the Tamyia paint and if it's still "too blue" dip it again. This ain't rocket science. I hate to work on either stock circuit boards or decoder boards with a soldering iron. Even with my Ungar adjustable heat station, it's way too easy to "lift" a trace, especially with lead-free solder they use now. I won't go off on why all of a sudden, after about 3000 years of using lead solder it's so "hazardous" now. 

[sizemore]

99% of "white" LED's will stand 4 volts positive. The 1% are the new super micros Richmond Controls sell. Pull the Kato LED and replace it with a more yellow LED, or easier, color the Kato LED's with an orange "Sharpie" or dip it Tamyia clear orange paint. I used Sharpie's on my Kato "blue laser" headlights, and they still look good after 5 or 6 years. I did about 20 Kato's for a customer at the shop with the Tamyia paint and if it's still "too blue" dip it again. This ain't rocket science. I hate to work on either stock circuit boards or decoder boards with a soldering iron. Even with my Ungar adjustable heat station, it's way too easy to "lift" a trace, especially with lead-free solder they use now. I won't go off on why all of a sudden, after about 3000 years of using lead solder it's so "hazardous" now. 

I think you totally missed what info I need, I need to know what type of LED was used on the Digitrax decoder. I replaced the surface mounted LED with the chance that it might not work. While browsing the Digitrax website I found their tech support number and got the answer I needed they say it's 3-4v white LED (even though their directions say orange).

What's more annoying is that the wires are in the passenger body and not hidden, so I cut channels in the chassis started routing the wires and realized I needed longer leads. So I solder them all up but for some reason I ended up with a cold joint after I got it all back together the cold joint snapped and I ended up launching the decoder into orbit. It's a shitty setup for a an "almost" plug and play decoder.

T

[mmyers]

If these are the Kato N scale  RDC's, They come with the light boards already set up for DCC. Remove the two screws in the board and reinstall one screw in the hole marked DCC. Then hook up the wires to the proper terminals. They are marked with a Y, W, and B.
I did mine years ago using DN140 wired decoders. This was before the Plug and Pray decoder came out.

Martin Myers

[Walkercolt]

The "new" decoder for the RDC's from Digitrax "drops in" with some small modifications to the long contact strips. You need to bend little "Vees" pointing upwards to make good contact, and taking the Kato floor out is a bit tricky, but they aren't that bad to install. You re-use the Kato LED's and their mount just snaps in. It took my buddy Carl a few days(on and off) to figure out the contact strip issue, and a few other "tricks" about the install, but now I think I (not the brightest DCC light on the string) could install one in under an hour, without breaking anything, having seen what he did. It seems like you're gonna take the entire RDC apart, but you don't. I wouldn't reccomend it for you're first decoder installation, but if I can figure it out(with help), it's not that bad.

[sizemore]

This was before the Plug and Pray decoder came out.

Martin Myers

This is pretty much sums up this decoder on a whole. I'm brighter than a 75 Watt bulb and somewhat skilled, but the engineering on this piece really sucks. The board is exposed and can float in it's "cradle" -too close to exposed contacts. I ended up coating some of the resistors with a buildup of Krystal Klear to get an insulator. Also soldered in the correct "Yellow Glow" LED's (Miniatronics 3-4v LEDs), now I just need to adjust the contacts for better pickup and I'm in the homestretch. Only 3 more to go.

T