EEVblog Electronics Community Forum

Electronics => Beginners => Topic started by: K3mHtH on August 06, 2016, 08:54:43 pm

Title: Help me replace this SMT LED!
Post by: K3mHtH on August 06, 2016, 08:54:43 pm
Hey everyone,
I need to replace this surface mount LED, but I'm having a hard time finding an equivalent on digikey. It shines at a right-angle (you can see the lens sticking out the right side in the picture), and it measures .12" at the widest point (top to bottom in pic), and .04" wide (left to right in picture) without lens and .09" including lens. It is about .03" off the PCB.



Title: Re: Help me replace this SMT LED!
Post by: Zero999 on August 06, 2016, 08:58:25 pm
What colour is it?

Are you certain the LED is faulty?
Title: Re: Help me replace this SMT LED!
Post by: K3mHtH on August 06, 2016, 09:03:35 pm
Quote from: Hero999 on August 06, 2016, 08:58:25 pm
What colour is it?

Are you certain the LED is faulty?

Hey Hero, it is currently RED and working but not very bright at all (it is used to edge-light a piece of plastic behind an LCD display) and I'd like to replace it with a brighter version. For colour, I'd be fine with RED or WHITE. My problem is that I'm not sure if this LED is considered 1204 in size, and if this is what digikey considers "Surface Mount, Right Angle" as the mounting type.

I'm not sure why this LED has gotten dimmer over the years, but from reading online it seems to be a common problem with this piece of equipment and everyone has had success replacing the LED's.


Title: Re: Help me replace this SMT LED!
Post by: pyroesp on August 06, 2016, 10:28:23 pm
Why not change the series resistor that limits the current through the LED ?
EDIT: Maybe R2 ?
Title: Re: Help me replace this SMT LED!
Post by: GBowes on August 06, 2016, 11:54:33 pm
Not easy to be sure of the size in your picture. If you measure the length and width you will know the package size. Yes, it is a right angle LED.
A 1204 package would be 0.120" by 0.040"
Graham
Title: Re: Help me replace this SMT LED!
Post by: Lee Leduc on August 07, 2016, 09:33:25 am
Mouser stocks Kingbright brand Right angle SMT LED's. Maybe you can find something similar here.

http://www.mouser.com/Optoelectronics/LED-Emitters/_/N-ec209?P=1z0z7pt&Keyword=kingbright+right+angle&FS=True (http://www.mouser.com/Optoelectronics/LED-Emitters/_/N-ec209?P=1z0z7pt&Keyword=kingbright+right+angle&FS=True)
Title: Re: Help me replace this SMT LED!
Post by: K3mHtH on August 12, 2016, 11:26:30 pm
Okay, replaced these LED's with some 1204 right-angle LED's.

Even though I measured, the 1204 replacements were a lot smaller than the originals.. not sure what that's about. But they did span the pads fine, and they worked.

So, I guess this thing had some LED's that went bad (very dim). Never seen that before!!