Справочник Пользователя для Apple MD094LL/A

iMac (27-inch, Mid 2010) — General Troubleshooting 

2010-09-09

Some test points are accessible on the logic board when the LCD panel is removed. The test points are defined 
below.

Logic Board Test Point Function
Pin 1

Ground

Pin 3

5V power for Hard Drive(s). Note: If present, the 12V power will 

come directly from the Power Supply to the Hard Drive thru the 

power harness cable.

Pin 4

Standby 12V power (permanent power coming from power 

supply and present as long as AC cable is connected, even if 

computer is off); corresponds to LED #1

Pin 6

Backlight Control pulse width modulated signal (from logic board 

to LED backlight board, to adjust the backlight level setting 

according to user setup)

Pin 11

12V Run-Mode power to logic board (coming from power supply, 

present as long as system is on or asleep); corresponds to LED #2

Pin12

Power On Request signal (from logic board to power supply 

when power button is pressed)

Pin 13

Backlight Enable (signal from logic board to Backlight Controller 

board, to enable backlight