Just purchased a NIB proto 2000 SD45 and installed a digitrax mobile decoder.
You'll never guess what happened, it blew the lights!
I knew it would happen, I just assumed it happened over time and they would't just blow.
So now I would like to install LEDs but not sure what size and resistance to go with. Any info helps a lot.
Thanks!
Ringo,
A few questions for you. Is the Digitrax decoder you installed a board decoder? Or, did you remove the lightboard that came with the SD45 to install the Digitrax decoder?
If the original bulbs were incandescent then they might have been 1.5V bulbs. If you removed the lightboard then you would have removed the built-in resistors that came with the lightboard; allowing the use of the lower voltage bulbs. If that were the case then they would have received 12V or higher and blown instantly.
Which Digitrax decoder did you install? Assuming it doesn't have built-in resistors, you will need at least a 1KΩ (1,000 ohm) resistor if you want to install 3V LEDs. And I would go with a "bridge white" 3mm LED for a SD45.
Does the SD45 have a lightpipe? Or was the incandescent bulb inside the lens of the headlight?
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
While it's a sound install, here's a link from the TCS website on a SD45 decoder installation:
https://tcsdcc.com/installation/ho-scale/1420
And it does confirm that they came with 1.5V incandescent bulbs. Given the photo of where the original bulbs are located, a 3mm LED should fit right into that same trough. And a piece of Kapton tape will hold it in place just fine.
tstage Ringo, A few questions for you. Is the Digitrax decoder you installed a board decoder? Or, did you remove the lightboard that came with the SD45 to install the Digitrax decoder? If the original bulbs were incandescent then they might have been 1.5V bulbs. If you removed the lightboard then you would have removed the built-in resistors that came with the lightboard; allowing the use of the lower voltage bulbs. If that were the case then they would have received 12V or higher and blown instantly. Which Digitrax decoder did you install? Assuming it doesn't have built-in resistors, you will need at least a 1KΩ (1,000 ohm) resistor if you want to install 3V LEDs. And I would go with a "bridge white" 3mm LED for a SD45. Does the SD45 have a lightpipe? Or was the incandescent bulb inside the lens of the headlight? Tom
I believe I removed the board. They blew pretty much as soon as it turned on, flashed once really bright.
I cant remeber the decoder I bought. I will take a picture of it later. It looks like an RC car battery. Has a wrapped portion with 10 wires coming out ( 8 going to the * pin harness and 2 for other functions)
And I believe the 45 has light tubes but unsure. I took the shell off and the bulbs were on the frame not the shell
tstage Ringo, While it's a sound install, here's a link from the TCS website on a SD45 decoder installation: https://tcsdcc.com/installation/ho-scale/1420 And it does confirm that they came with 1.5V incandescent bulbs. Given the photo of where the original bulbs are located, a 3mm LED should fit right into that same trough. And a piece of Kapton tape will hold it in place just fine. Tom
I would need a resistor, correct? If so, what ohm?
Tom has already given you some great advice.
Your description of a blown incandescent bulb is spot on. Don't ask me how I know.
Yes, you would need a resistor on one leg of the LED. I would suggest a 1K ohm, 1/4 watt resistor. I mention 1/4 watt because a 1/4 watt resistor is smaller than a 1/2 watt resistor and takes up less space under the shell.
You should use heat shrink tubing on both legs of the LED and cover the resistor with heat shrink tubing in the process to prevent any possibility of shorting the LED.
Rich
Alton Junction
I use clear caulk to glue LED's in place. Some people use CA to glue them to light pipes.
LED's have a polarity that needs to be respected, if you want light out of them. I can never remember which lead is which, so I keep a picture of an LED and the color codes for DCC wire (which I also can't remember)
Henry
COB Potomac & Northern
Shenandoah Valley
BigDaddy I use clear caulk to glue LED's in place. Some people use CA to glue them to light pipes. LED's have a polarity that needs to be respected, if you want light out of them. I can never remember which lead is which, so I keep a picture of an LED and the color codes for DCC wire (which I also can't remember)
The shorter lead on the LED is negative (-). One other way to identify the negative side of the LED is to look inside the casing and find the larger piece of metal which is the negative side. The negative side of the LED connects to the COMMON tab on the decoder, and it is typically associated with the blue wire on the decoder.
I use these for Life-Like installs and they're handy for several others as well:
https://www.ebay.com/itm/253170051561?hash=item3af21c69e9:g:RVYAAOSwHUhaAsX-
I've bought several other sizes and styles from other sellers as well.
Just installed a backup light in an Atheatrn Genesis B unit last night using one.
I don't recall taking photos of my SD45 install but this is a L-L SD-7:
SD_9-decoder-sp3 by Edmund, on Flickr
And this one in a Genesis GP9-B
GP9b_PRR_Tsunami2a by Edmund, on Flickr
Temporarily taped in place. I sometimes use "Sticky-Dots" to hold them. this stuff can be repositioned or easily removed. Technically it is called fugitive glue.
Good Luck, Ed
I've always found this diagram helpful for identifying the various parts of an LED:
In reality it doesn't matter which lead of the LED you solder the resistor to. However, I would pick one as your standard for consistency. If you should ever end up trimming both LED leads shorter to make the LED fit the space requirements of the shell or the chassis, it will make identifying the cathode (-) side of the LED quicker visually.
BigDaddySome people use CA to glue them to light pipes.
Personally I find it easier to use black heat shrink as the interface between the LED bulb and the lightpipe. Otherwise, you have to flatten the ends of the LED and the lightpipe with a file to maximize the surface area for gluing.
The black heat shrink also helps to minimize any extraneous light from being cast inside the shell area. That probably won't be an issue with Ringo's SD45 but would be for an LED in the cab area of a small switcher or an F-unit.
It also makes LED replacement much quicker and easier. Yes, LEDs are supposed to last "forever". However, they can and do burn out.