Re: How to salvage SMD LEDs from heatsinked surface

Did not think to try powering up, told broken.

11W large LED omniderectional room light, Medion Lifelight, 1055 lumen. Easy enough to break into, the globe opalate glass is just for diffussion, no vac inside. Tried powering up the LED disc with 60V bench ps and no light. Uses BP2812, max 135mA drive from the datasheet and application much as in the datasheet,also 22R 1W in the supply line. 36 LEDs so probably 1 string and a chain is only as strong as its weakest link. So supply probably > 120V at 100mA and 60V would not have lit a working one anyway. First tried a fairly isolated LED, preheating the Al heatsink disk then freezer spray , then more hot air and tugging on the LED just broke it up. At least it showed which end was the heatsink terminal pair plus underlying pad. Cathode end is chamfered corner and feint dot under the optical surface on these SMD LEDs. Heatsink pad to anode. So tried a single edged old type razor blade. With shearing and slight saw action cut under the LED anode end first, angled down into the disk layup and when just sheared , finger over the body of the LED to hold down while shearing the cathode end pair of pads. Insulator plus traces layup shears from the Al disc, leaving quite clean reusable LEDs. They all tested working order except the first obviously, another one that I forgot to hold a finger to and it split in the middle and one that looked fine, presumably the original failed one. Much more interesting , and other useful stuff , inside these new fangled lamps , including CFL, 400V 125 deg C caps, diacs etc than old boring filament lamps
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N_Cook
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N_Cook kom med følgende:

As a kid, I unrolled capasitors from junked tube radio/tv's to find something interesting inside. But after I removed all the wrapping, there was nothing. Very disappointing...

Leif

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Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske  
beslutning at undlade det.
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Leif Neland

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