Also had this (once!) when changing a front glass.
The power disconnect method works but you have to be very careful not to use anything metallic.
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I have seen this on laptops with b0rked CCFL/LEDs before and once actually toyed with the idea of getting an EL backlighting panel for an old 22" screen until the price list came up- $200 for a panel!!!!
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I have seen this on laptops with b0rked CCFL/LEDs before and once actually toyed with the idea of getting an EL backlighting panel for an old 22" screen until the price list came up- $200 for a panel, although EL wire of the high brightness type arranged in line with the horizontal axis will work for those extra spooky projects :-) (about 10.6 metres for the screen I have)
The reason why that little diode is important is that with the 4R7 coil it makes a boost converter that steps up voltage to 16.5 volts for the series string of LEDs and then another component regulates the current to provide brightness adjustment.
Pretty sure that in common with other panels there is a thermistor somewhere so if the LEDs begin to heat too much it backs off the current so they don't (a) change colour or (b) fry.
White LEDs have quite a narrow range of currents where they have the correct spectra.
A good source of compatible diodes and 4R7's is old laptop LED panels which often get trashed because the glass is broken, with basic skills and thin solder this is an easy though fiddly repair.
Also had this (once!) when changing a front glass.
The power disconnect method works but you have to be very careful not to use anything metallic.
I have seen this on laptops with b0rked CCFL/LEDs before and once actually toyed with the idea of getting an EL backlighting panel for an old 22" screen until the price list came up- $200 for a panel!!!!
The reason why that little diode is important is that with the 4R7 coil it makes a boost converter that steps up voltage to 16.5 volts for the series string of LEDs and then another component regulates the current to provide brightness adjustment.
Pretty sure that in common with other panels there is a thermistor somewhere so if the LEDs begin to heat too much it backs off the current so they don't (a) change colour or (b) fry.
White LEDs have quite a narrow range of currents where they have the correct spectra.
A good source of compatible diodes and 4R7's is old laptop LED panels which often get trashed because the glass is broken, with basic skills and thin solder this is an easy though fiddly repair.