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Apple Computing Products:
macOS - Desktop Hardware
Need LCD driver info (BL_ON and PWM) to convert dead 27" iMac into monitor
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<blockquote data-quote="Stokestack" data-source="post: 1846864" data-attributes="member: 404255"><p>Well, I found the info elsewhere. I'll post it here in case it's useful to anyone in the future.</p><p></p><p>The 2011 iMac display backlight system uses pulse-width modulation (PWM) to control backlight intensity. A PWM control signal is generated within the logic board-video card circuit and routed to the PWM input on the backlight board. The PWM frequency is 13KHz and the pulse height is 3.25V. The duty cycle is varied from 0 to 100% to adjust backlight intensity from minimum to maximum.</p><p></p><p>You can reportedly turn the backlight on by supplying +5V to the BL_ON wire.</p></blockquote><p></p>
[QUOTE="Stokestack, post: 1846864, member: 404255"] Well, I found the info elsewhere. I'll post it here in case it's useful to anyone in the future. The 2011 iMac display backlight system uses pulse-width modulation (PWM) to control backlight intensity. A PWM control signal is generated within the logic board-video card circuit and routed to the PWM input on the backlight board. The PWM frequency is 13KHz and the pulse height is 3.25V. The duty cycle is varied from 0 to 100% to adjust backlight intensity from minimum to maximum. You can reportedly turn the backlight on by supplying +5V to the BL_ON wire. [/QUOTE]
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Apple Computing Products:
macOS - Desktop Hardware
Need LCD driver info (BL_ON and PWM) to convert dead 27" iMac into monitor
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