Apple imac 17in 1ghz Servicehandbuch

2 - iMac (17-inch Flat Panel, 1GHz) Troubleshooting

General Information

have new thermal paste applied each time the bottom housing is removed. If the mating surfaces are

not cleaned and thermal paste is not used, the CPU may overheat and become damaged. There is no

exception to this. Note: Most service procedures require that the bottom housing is removed.

Refer to “Thermal Paste Application” mentioned later in this chapter or in the Take Apart
chapter.

Whenever the LCD display (661-2715) is replaced, a display shield/gasket kit (076-0958) must be

installed on the new panel. Instructions for installing the shield/gasket kit are included with the new

LCD panel.

The LED and microphone are part of the display bezel (922-5297); they cannot be ordered separately.

The LED functions differently on the iMac (17-inch Flat Panel). The LED does not light up when the

power is on; however, the LED should pulse when the computer is in Sleep mode.Important: If you are

replacing the display, be sure to install the new display shield and EMI gaskets that come with the new

LCD panel. Installation instructions are included with the new display panel. Additional display shields/

gasket kits are also available separately as a kit, part #076-0958.

Important: Whenever the logic board is separated from the bottom housing, you must install new

thermal pads to two surfaces on the bottom housing. The thermal pads help cool components on the

logic board. Failure to apply these pads whenever the logic board is separated from the bottom

housing could cause these parts to overheat. Short term separation, where the thermal pads are not

handled excessively

( an exception would be if you are simply testing the logic board and only detach it

for a few minutes), does not require replacement. Refer to “Thermal Pad Installation” in this chapter for

detailed information.

Refer to the Take Apart chapter, “Thermal Pad Installation.”

Whenever the bottom housing is opened for service, you must do two things:

1.You must clean the original thermal film from the surfaces joining the thermal interface layer and

reapply thermal paste to the thermal pipe.

2. You must tighten the four torx screws on the bottom housing to a minimum of 17 in.-lbs. If you do

not have a torque driver, you will have to make sure these screws are tightened by hand FIRMLY,

BUT NOT FORCIBLY. Or, purchase the service tool (076-0899) in order to ensure the thermal pipe is

firmly mated with the top base. If the bottom housing is not securely attached to the base in this

fashion, the CPU may overheat and become damaged. Failure to follow either of these steps could

cause the computer to overheat and damage internal components.

Refer to the topic, “Thermal Paste Application” for detailed information.

A service stand, 076-0898, is available from Apple Service to hold the unit while you service the

computer.