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Hi all.
I have one of the many 2010-era Macs with failed GPUs. In this case, a 27" iMac. I've gutted it of everything except the LG panel, the power supply, and inverter board. I do not have the motherboard anymore, so I can't trace anything back to it.
I bought a cheap LCD driver off eBay, which comes with its own video board and inverter board. I'm powering it with one of the 12V outputs from the original power supply. The original inverter board is currently unused.
The driver board works; a video signal into the board's HDMI port is indeed displayed on the screen. But, as one review stated, the brightness range seems to fall short of the original setup.
I figure that this is due to the cheap inverter board, so I'd like to use the original inverter. The original inverter board identifies the BL_ON and PWM lines. The question is how I use them. I ordered some cheap PWM generators that have adjustable frequency and duty cycle, but I don't know what frequency and voltage the iMac inverter expects on the PWM line.
Also, how do I use the BL_ON line to turn on the backlight? I saw in a thread somewhere that someone found 3.3V on it when it was on, but this may have been a laptop.
Thanks for any insight!
I have one of the many 2010-era Macs with failed GPUs. In this case, a 27" iMac. I've gutted it of everything except the LG panel, the power supply, and inverter board. I do not have the motherboard anymore, so I can't trace anything back to it.
I bought a cheap LCD driver off eBay, which comes with its own video board and inverter board. I'm powering it with one of the 12V outputs from the original power supply. The original inverter board is currently unused.
The driver board works; a video signal into the board's HDMI port is indeed displayed on the screen. But, as one review stated, the brightness range seems to fall short of the original setup.
I figure that this is due to the cheap inverter board, so I'd like to use the original inverter. The original inverter board identifies the BL_ON and PWM lines. The question is how I use them. I ordered some cheap PWM generators that have adjustable frequency and duty cycle, but I don't know what frequency and voltage the iMac inverter expects on the PWM line.
Also, how do I use the BL_ON line to turn on the backlight? I saw in a thread somewhere that someone found 3.3V on it when it was on, but this may have been a laptop.
Thanks for any insight!
