replacing an led - Page 1
Forum section: electronics / repair

author: jimjam
author_rank: Regular Contributor
timestamp: August 03, 2020, 08:25:57 am
content: I would like to replace two LEDs with different colours. I don't know exactly what these LEDs packaging is called and where to buy a replacement. I just need one or two {as a spare in case I stuffed up) for each colour. I want to replace two blue LEDs with one green and one orange.They are the power indicator leds behind the buttons on the deta power switchhttps://www.bunnings.com.au/deta-grid-connect-smart-triple-gang-touch-light-switch_p0161014Pic attached. The distance between the two soldered points is roughly 1.8mm, roughly being the key word. I used a caliper but it's tiny.Perhaps an easier solution is to apply a coloured plastic filter on top of them? Not sure how blue can be changed into green / orange thoughThanks for any tips.

author: sleemanj
author_rank: Super Contributor
timestamp: August 03, 2020, 09:05:27 am
content: Probably "0603" (1.5mm x 0.8mm), but "0805" (2.0x1.3) will likely fit also.Destructive removal is easy just put your soldering iron across the side of the led to melt both pads at once.To put the new ones on, clean the excess solder from the pads, apply solder to one pad, while keeping that solder molten slide the LED (in the correct orientation) into place, remove iron, let solder cool, and do the other end.Edit to add: the codes above, 0603 and 0805 are the far more commonly used "imperial" (that is 0603 measures 0.06 x 0.03 inches), care should be taken in the case especially of 0603 because that's also a common metric code for a totally different and much much smaller size, you don't want to order LEDs that are 0603 metric!

author: Ian.M
author_rank: Super Contributor
timestamp: August 03, 2020, 09:10:25 am
content: Green and orange, yellow or red LEDs typically have a much lower Vf than blue and white LEDs, so may draw too much current from the circuit driving them unless you change any series resistor present. OTOH the driving circuit may directly control the current so the LED Vf may not matter. It also may not matter if the driving circuit can handle the extra current, its less than the new LED's If_max, and you don't care much about the brightness, which may be excessive.An alternative which maintains a similar Vf would be to replace them with white LEDs then filter the light with a dab of coloured nail varnish.Re-take the photograph with a slip of 1mm, 10mm square graph paper or a small metric machinist's rule butted up to the side of the LED for scale, and we can work out the SMD package size and point you at some distributors.

author: jimjam
author_rank: Regular Contributor
timestamp: August 05, 2020, 02:37:29 pm
content: This is another photo with a ruler. The distance between two lines is 0.5mmIt connects in series with an R that says 1001 (is it 1k?) A diode, then onto a pin of an esp8266 (3.3v).

author: Ian.M
author_rank: Super Contributor
timestamp: August 05, 2020, 05:44:26 pm
content: An ESP8266 can source/sink in excess of 10mA, With a 1K series resistor you can't get more than 3.3mA with the LED shorted so you can swap LEDs without changing the resistor. Measuring from your latest photo it appears to be 1.6mm x 1.2mm, which matches a 0605 (or 1612 metric) package. You should have no problem finding them at any major distributor.

author: jimjam
author_rank: Regular Contributor
timestamp: August 06, 2020, 02:14:30 am
content: Thanks for all the info. Maybe I can get this one, and just solder one or the other to get green or yellow:https://au.rs-online.com/mobile/p/leds/8609052/

author: Ian.M
author_rank: Super Contributor
timestamp: August 06, 2020, 02:47:12 am
content: While you could *IN* *THEORY* do that, RS supplies that part in packs of 50, so that would be rather expensive! Also, overhanging half its width without a pad to solder to vastly increases the risk of ripping pads of the board if it ever gets knocked.

author: jimjam
author_rank: Regular Contributor
timestamp: August 06, 2020, 03:22:05 am
content: Where can I get individual leds?