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Introduction |
Thunderbolt Display uses an LG edge LED lit LCD Display (also 09-11 27" iMacs and 27" Cinema Displays) uses an LG edge LED lit LCD Display. The LEDs are on the bottom edge of the display. There are 2 bars (left and right) Each bar has many LEDs and a 6 pin connector. Each pin drive several LEDs thus is the highest current flow / heat junction. The weak lead free solder gradually fails with thermal expansion/contraction cycling and increases resistance. PSU will compensate up to a point, then when the current is too high, PSU just shut down the backlight causing a dark display. I have even seen one which the connector just fell off as solder points became completely detached. | | | Usually this problem starts manifesting itself with brighter settings only. Can work around by reduce brightness. Eventually, even the lowest brightness won't work anymore. |
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