Nacelle Lighting Help

[cappy]

I have a question on surface mount LEDs. I'm contemplating the idea
of swapping out the Red surface mount LEDs on a Sparkchaser Electronics,
Ultimate nacelle lighting kit to blue ones.

Is this possible and what pandoras box might I be opening. The kit is for the 1/1000 TOS E, so the board that the lights are on is 1/2" dia. Which is perfect for my needs but small for my skill set.

Any advise or guidance, would be appreciated.

[USS Atlantis]

I have a question on surface mount LEDs. I'm contemplating the idea
of swapping out the Red surface mount LEDs on a Sparkchaser Electronics,
Ultimate nacelle lighting kit to blue ones.

Is this possible and what pandoras box might I be opening. The kit is for the 1/1000 TOS E, so the board that the lights are on is 1/2" dia. Which is perfect for my needs but small for my skill set.

Any advise or guidance, would be appreciated.

Main thing to watch out for is voltage requirements

I'm not sure on the particulars of those exact SMD LEDs, but the one's from my supplier are just like normal LEDs

3v for Blue
2v For Red

So if you just do a direct replacement without replacing the resistor tied to that LED, then you're just asking for burnout

[tetsujin]

3v for Blue
2v For Red

So if you just do a direct replacement without replacing the resistor tied to that LED, then you're just asking for burnout

Well, going from red to blue would be safe, you just might not get as much output as you want...

[USS Atlantis]

3v for Blue
2v For Red

So if you just do a direct replacement without replacing the resistor tied to that LED, then you're just asking for burnout

Well, going from red to blue would be safe, you just might not get as much output as you want...

True, that would be safe

And I just calculated out the difference

Assumption

Source is set for 6v input

Red LED's (2v@20ma)need a 200 ohm resistor

Running a 5000 mcd (max)Blue LED (3v@20ma) with the 200 ohm resistor will drop the output to 3750mcd

YMMV

[mhvink]

I think a bigger concern is not electrical, but mechanical. Surface-mount components are extremely sensative to the heat of a soldering iron. It isn't as easy to mount as a through-hole, leaded part. Use the heat sparingly and try not to leave the iron on the part too long. That is a recipe to unbond the metal tab on the side of the LED and ruin it.

Just my 2c.

Mike

[Often wrong Soong]

Yeah thats true, those tiny guys are REALLY fragile! You'd need a very fine tip on your iron and, as mhvink says, you gotta use the heat very sparingly. I used to remove surface mounted IC's using a stereo microscope in my old job and spend forever trying to replace damaged or burned out components until I got the hang of it!!!

[Madman Lighting]

Ditto on being gentle with those surface mount LEDs.

I usually put the iron on the side of the part, so both ends heat at the same time, then just "wipe" the part away. It helps alot to use a little solder braid to remove any remaining solder too. A nice, flat smooth pad makes attchment much easier.

-John C.

[tetsujin]

I think a bigger concern is not electrical, but mechanical. Surface-mount components are extremely sensative to the heat of a soldering iron. It isn't as easy to mount as a through-hole, leaded part. Use the heat sparingly and try not to leave the iron on the part too long. That is a recipe to unbond the metal tab on the side of the LED and ruin it.

In my experience this also varies a lot according to the specific LEDs being used. Some of my SMD LEDs are simply nightmarish to try to attach (and keep attached) to wires. Others are a lot easier to work with. I think it has to do with the design of the contacts - after all, these LEDs weren't really meant to be attached to the ends of wires, but rather to circuit boards...