Mid 2010) | Apple Technician Guide Imac (27-inch,

Remove eight T10 screws. Carefully tilt the panel to disconnect four critical cables: Vertical sync cable. Backlight power cable. LCD temperature sensor. DisplayPort data cable.

Use an external monitor to determine if a display issue is caused by the LCD/cable or a failing graphics card/motherboard. Apple Technician Guide iMac (27-inch, Mid 2010)

A black display does not always mean a bad LCD or GPU; a broken video signal connector on the LCD can prevent the backlight from turning on entirely. Remove eight T10 screws

Requires pushing through the RAM cavity for easier release. Troubleshooting & Common Issues Apple Technician Guide iMac (27-inch, Mid 2010)

Use suction cups to pull the glass panel away. It is held by magnets.