I need to replace an LED on the front panel of a piece of equipment. I want to match the other LEDs, both in terms of color and intensity. If I am unable to get an original part from the manufacturer, what is the process to match a dead LED?
There are five other identical working LEDs on the panel I could use for reference.
There are five other identical working LEDs on the panel I could use for reference.
Can you get a part number from the manufacturer? Without that there is very little chance of finding an exact match. They are all so different in color and brightness.
If the LED (or one of its brethren) is working, you can measure the Vf as a start. You can then measure the diameter of the LED with calipers to fit the aperture in which it is fit, etc., etc. DK search engine will help you the rest of the way.
Make sure you run the same current through the replacement LED so pick the right size and color and the same series resistor (this as a starting point when trying out a similar but not equal replacement LED). If you don't have your lucky day you will notice that (for instance) a new green LED will be brighter at the same current as older green LEDs. We don't know the brand, type or age of your piece of equipment or even the color of the mentioned LEDs (do you want to buy my car? It is red) so we can't say anything useful really. If the device is older chances are likely A brand LEDs were used where todays ChiFi devices will have cheap LEDs and these differ both in color and brightness. Best is to have the type number of the original ones if you want things to be 100% equal.
If it is old equipment so quite old LEDs with many hours on them even with a 100% same LED you might need to play around with a potentiometer for correct brightness before mounting "a LED in a piece of equipment*" with a resistor of the found value. I think the issue of differences is occurring most with old/new red and old/new blue LEDs.
*It is hard to give away usable info to help us to solve your issue isn't it?? You will need "a LED and a resistor" 😀
If it is old equipment so quite old LEDs with many hours on them even with a 100% same LED you might need to play around with a potentiometer for correct brightness before mounting "a LED in a piece of equipment*" with a resistor of the found value. I think the issue of differences is occurring most with old/new red and old/new blue LEDs.
*It is hard to give away usable info to help us to solve your issue isn't it?? You will need "a LED and a resistor" 😀
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You may also change all the leds with new ones…
With recalculated series resistors as new LEDs are way brighter than old ones. Decades old LEDs in the standard colors green/amber/red needed 10 mA to have some output. Today I find recent green LEDs to glow quite bright at 2.5 mA. The recent blue ones are (besides ugly search lights) already too bright at ....1 mA. Recently I repaired a ChiFi 5V PSU that had a red LED with 10 kOhm series resistor that still was too bright. That is less than 0.5 mA....
Rled = Ubat - ............
Rled = Ubat - ............
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The unit is a Rega Aria, and the LEDs are red. There's a note on the main circuit board that says it was manufactured in 2018. So, hopefully the age of the LEDs wont be a problem. I'm trying to track down original parts, which would obviously be best.
It sounds like brightness is going to be the biggest concern? Could I measure the voltage drop across the current LEDs to work out the spec? It's a SMD part, and there isn't an easy place to insert a series resistor, I'd have to mod something up.
It sounds like brightness is going to be the biggest concern? Could I measure the voltage drop across the current LEDs to work out the spec? It's a SMD part, and there isn't an easy place to insert a series resistor, I'd have to mod something up.
LEDs are current driven and there will be series resistors definitely.
Unless the original SMD LED really is defective it is maybe better to leave the device as it is.
Unless the original SMD LED really is defective it is maybe better to leave the device as it is.
Seems to be. It's getting voltage but not illuminating.
Whatever series resistor there is applies to this and the other input indicator LED. So I couldn't change it just for the replacement. I suppose I could replace both this and the working LED so they would share the same series resistor.