Apple IMAC Service Source - Page 49

Warning: Whenever the bottom housing is opened for service, you must do two things: 1.You must clean the original thermal film from all thermal interface mating surfaces, and reapply thermal paste to the mating surfaces on the thermal pipe. 2. You must tighten the four torx screws on the bottom housing to a minimum of 17 in.-lbs. Use a torque driver (service tool 076-0899) to ensure that the thermal pipe is firmly mated with the top base. If you do not have a torque driver, you must make sure the screws are tightened by hand FIRMLY, BUT NOT FORCIBLY. Failure to follow these steps could cause the computer to overheat and damage internal components. Refer to the topic "Thermal Paste Application" for detailed information. Warning: Whenever the logic board is separated from the bottom housing, you must install new thermal pads to three surfaces on the bottom housing. Failure to apply these pads whenever the logic board is separated from the bottom housing could cause these parts to overheat and could damage internal components. Note: AFTER installing new thermal pads, if you must briefly re-separate the logic board from the housing, it is OK to retain the same, new pads as long as they are not handled excessively. Refer to "Thermal Pad Installation" in this chapter for detailed information. 40 - iMac (USB 2.0) Take Apart AC Line Filter