Is the center pad of these 1w LED's soldered? - Page 1
Forum section: electronics / beginners

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 02:46:44 am
content: Hey all, so I may need to swap some LED's soon, ones that use this sort of package.http://image.dhgate.com/albu_568068486_00/temp2.0x0.jpghttps://www.led-tech.de/images/products/resized/LT-1508-1235125369.jpg(they don't have the board on them, just another example)They have a central metal pad on them, and I was wondering if that gets soldered as well, or if it's just the two leads, and the metal pad on the LED is just relying on physical contact with the pcb for heatsinking.I just want to know if I can replace these with an iron, or if I'd need a hot air gun.

author: Brumby
author_rank: Unknown
timestamp: February 24, 2017, 03:08:07 am
content: You only need to connect the two tabs, so hand soldering with an iron is the way to go.The metal pad is for heatsinking, so close contact across this surface is needed. When I soldered a few to the same type of star-shaped board recently, I added a tiny amount of good quality thermal compound (Noctua NT-H1) and made sure the LED was well seated.Don't know if the thermal compound was a good or bad idea - but time will tell.

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 03:20:35 am
content: Yeah, I figured I could use thermal paste as well, wouldn't be as good as solder, but I have no clue if they are soldered down in the first place or not, I'll only know when I go to take it off. They do get quite toasty, though they won't be on steadily for long periods, they are strobing more than anything.

author: amitchell
author_rank: Regular Contributor
timestamp: February 24, 2017, 04:23:51 am
content: You really should be soldering down the thermal pad if it has one, preferably with .25 to .3mm thermal vias to other layers.I know this is not the led you have but it is a good reference.http://www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/XLamp%20Application%20Notes/XLamp_PCB_Thermal.pdf

author: sleemanj
author_rank: Super Contributor
timestamp: February 24, 2017, 04:41:26 am
content: I just use double sided thermal transfer tape (heatsink tape). Use a hole punch to punch out circles of the right diameter (a single-hole handheld punch is easiest but a normal double punch is fine too).Have used thermal grease in the past but it can be a bit messy (especially when you are as clumsy as I am).

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 12:30:12 pm
content: Hmm, so the ones already in there will most likely have that part soldered, darn.

author: sleemanj
author_rank: Super Contributor
timestamp: February 24, 2017, 12:56:47 pm
content: Quote from: XOIIO on February 24, 2017, 12:30:12 pmI would be surprised if the center pad was soldered, especially on any typical chinese manufactured assemblies.

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 01:13:42 pm
content: Quote from: sleemanj on February 24, 2017, 12:56:47 pmIt's not typical cheap stuff though, these are on automotive strobe lights, the exact type police use, manufactured by whelen. The boards have con formal coating and it's all surface mount from what I recall, so it's probably a safe bet that they are soldered down.

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 01:17:39 pm
content: Hmm, I wonder if there are adapter tips for this so that I could use it like a rework gun, the digital control would be great, but it's pretty unwieldly and more than I'd like to spend. For that much I may as well get an ebay hot air station.http://www.princessauto.com/en/detail/digital-control-electric-heat-gun/A-p8327835e

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 01:28:21 pm
content: Hmm, here's a cheapo, and I could probably make most of the cost back fair quickly if it worked well.https://www.amazon.ca/Sigma-Desoldering-Station-Digital-Displays/dp/B00UH90G9Y/ref=sr_1_1?ie=UTF8&qid=1487942840&sr=8-1&keywords=hot+air+stationNot sure how much shipping is off hand.

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 01:30:20 pm
content: Hey, there's a free shipping option, sweet. I know these things aren't great quality but they generally do the trick from the videos I've watched testing them and doing teardowns.

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 02:42:52 pm
content: I wonder if that sigma is a rebrand of the atten 858d dave reviewed, I remember him being enthusiastic about it, re watching the video now.

author: XOIIO
author_rank: Super Contributor
timestamp: February 24, 2017, 03:06:10 pm
content: Alright screw it, looks similar enough, it's on sale, and I've wanted one for years, same with a desoldering gun. If I didn't have a job I wouldn't, but I actually got one so I'm going to pull the trigger on this puppy.

author: amitchell
author_rank: Regular Contributor
timestamp: February 25, 2017, 12:02:28 am
content: https://www.walmart.com/ip/Embossing-Heat-Tool-with-Stand/10310557I use my wifes embossing tool