Chosen Solution
Hi all. I’ve gutted a 27” iMac that suffered the near-universal GPU failure, and I’m converting it into a monitor with a cheap LCD-driver board from eBay. Instead of a likewise cheapo PSU and inverter, I’m trying to use the original Apple ones. I found a pinout of the PSU’s output connector, but don’t know what some of the abbreviations mean or their function. Can anyone help? I don’t have the motherboard to trace anything back to, so that’s not an option.
Update (07/27/2020) Well, I got the whole thing working. I ran a switch to ground the PS_ON line as required, which activates the stock PSU. The PSU has several 12V outputs, so one of them powers the LCD driver board, another goes through a converter to provide 5V to the backlight-on signal, and another gets converted to 3.3V for a PWM module to control the backlight brightness at 150 kHz. The LCD driver board had its own power supply for the backlight, but some reviews said it asn’t as bright as the stock one so I added the PWM module to drive the stock one.
The only lines that you can use is the PP12V & GND pins (3 + & 5 - pins) 12 Volts + and - PS ON is the power switch line with shorts to GND to enable the power supply (soft on)
I used this solution to start/stop the power supply from the button without locking, using original power button. K561LE5 (analog CD4001A) + mosfet IRF3205 C - 0,1 , R1 - 10k, R and R2 - 100k Use U+ from PP12V_G3H_ACDC, mosfet connect drain to PS_ON It is work fine
