.:madworm:.'s photos with the keyword: dead

Not proud of it, but I HAD to take action. These little buggers wouldn't leave on their own.

It's sitting in my living room right now, but I think it is dead. All leafs go brown. I'll give it another month.

Initially I was very pleased with these 5 chip 1/2 Watt LEDs I acquired from ebay. For testing I ordered 10pcs of the warm-white type (100,000 mcd @ 100mA), which are shown here, and 10 pcs of neutral/cool-white (120,000 mcd @ 100mA). NONE of the latter have failed so far. I use constant current LED drivers, therefore it shouldn't have been over-current that has killed them. 3 in a row. Now will I use these, or search for equivalent/better SMD types? As it turns out, I won't use the warm-white type at all, it doesn't look good on the kitchen counter at all.

I think I will never ever again use LEDs of this class without a _real_ constant current source. Just using resistors doesn't cut it anymore. Especially when one of the LEDs fails shorted... I was thinking about using a 2N2222 for that purpose, but didn't. Silly me

I think I will never ever again use LEDs of this class without a _real_ constant current source. Just using resistors doesn't cut it anymore. Especially when one of the LEDs fails shorted... I was thinking about using a 2N2222 for that purpose, but didn't. Silly me

Once in a while I sell one or two of the RGB LED RING boards. As not everybody feels comfortable with soldering SMD parts (and I've explicitly warned that it's not that easy and that the RGB LEDs die easily) I do some 'contract soldering' from time to time as well. Today I've killed 3 - THREE - of these friggin' things, and I only have about 10 spares left. That's a loss of more than 1€ of semiconductor. Time to get more spares it seems. In this shot I managed to show what's going belly up here. It's always the green ones that die. As shown here, the bonding wire has been ripped off the left pad due to stress. Looking at this image again a few hours later, it seems the whole pad has moved to the left opening a gap of maybe 0.1mm. What a heap of shit. Could the surface tension of the solder create such a big force and pull the pad out of the somewhat softened plastic body? I'm trying to keep the heat down and be quick, but today was a very bad soldering day. I have a feeling they wanted to save time and material in the bonding process and the wires are a bit overstressed anyway. Maybe they also 'tweaked' the gold content a bit and it got too brittle. If these LEDs are soldered in a reflow oven this problem might not occur at all, as the epoxy around the wires will soften a bit. Given the correct temperature-vs-time profile is used. Time to get an SMD toaster? Maybe. Any recommendations? Hotplate? And I don't want to spend a fortune on it as well. Oh BTW, I hate things that suddenly just sublimate without any signs of warning! I'm looking for reasonably priced quality products here. Nothing fancy, but fully functional with a minimal amount of cursing. Today was also the very first time that I just couldn't reliably upload code using a bootloader with the chip running on the internal 8MHz RC oscillator. Maybe this is due to the somewhat elevated temperatures we're having here right now. It's in the middle of the night right now and I'm still getting 26°C in my room. Or maybe this AVR's factory calibration is just terribly wrong. Luckily I had previously assembled another one of the boards, so I just swapped them. The good one is sent away and I keep the rebellious one for further testing. I'll put it into the freezer tomorrow and see what happens to it.

Initially I was very pleased with these 5 chip 1/2 Watt LEDs I acquired from ebay. For testing I ordered 10pcs of the warm-white type (100,000 mcd @ 100mA), which are shown here, and 10 pcs of neutral/cool-white (120,000 mcd @ 100mA). NONE of the latter have failed so far. I use constant current LED drivers, therefore it shouldn't have been over-current that has killed them. 3 in a row. Now will I use these, or search for equivalent/better SMD types?

Seems it was a wise decision to use a socket for this one. Side note: now I know what I forgot. A voltage regulator. And connecting a 5V board to a 12V board will only create one thing: acrid smoke.

I don't know how I killed it, it suddenly didn't do its job anymore. Maybe static electricity. Fortunately the failure mode was to output 0V and not 12 ;-)