Ok I just recieved a pack of 3v surface mount led in the mail. Plan on using them on several engines that have strobe lights mounted in the cab roof.
So the question is on the nce dasr decoder pads 3,4,5 for lighting functions, are they rated for the 3 volts or are they getting full track powrer of 15 volts? I looked in the pamphlet that came with the book and it does not say. Any one have any advise on this? If I need a resistor wired in what size do I use so I dont blow out the led( only have a handful so I can only mess this up about once). Any one have any pics of using these pads and how they used them for lights?
Thanks in advance.
Mike
alco's forever!!!!! Majoring in HO scale Minorig in O scale:)
The output for 3 and 4 are track voltage so you will need a resistor for each LED
https://ncedcc.zendesk.com/hc/en-us/article_attachments/200598339/dasr.pdf
See page 2 and page 6.
Good Luck, Ed
The first DA-SR manual I googled up didn't have any pads marked 4,and 5. The latest version does, at the bottom of this page
https://ncedcc.zendesk.com/hc/en-us/articles/201382145-DA-SR-HO-solder-in-decoder-5-functions
At the bottom of page 5, it says to use 1K 1/4 resistors for function outputs.
The led has 2 leads, one has to be soldered to the common pad or spliced into the appropriate blue headlight lead (+). The other has to go to one of the function pads.
Knowing what I know now, and if I had the room, I'd use one of Mel's microplugs on the strobe light, so the shell could be completely disconnected from the chassis. Although once it all works, I have not had a reason to disassemble any locos.
How are your surface mount led's marked for polarity? I see conflicting things on the "net?
Henry
COB Potomac & Northern
Shenandoah Valley
thanks for the info. as for polarity I have not dug that far into the project yet. just got them the other day and have had a couple of shells to strip before getting into the led stuff.
mike
So i used a 650ohm 1/4 watt resistor and got a good light. It would be the lowest value i would go with I think. The 1000 ohm 1/4 would be better for longer life probably but it was fairly dim by the time it came out the strobe. Thanks all for the advise you gave. It steered me in the right direction.