Apple Hardware Test

Apple Hardware Test is a diagnostic tool for detecting problems with Apple internal hardware components such as logic board, memory, modem, video RAM, and Apple AirPort Card. The test does not check externally connected hardware components such as USB or FireWire devices it also does not check nonApple devices such as third-party PCI cards. Note The most recent Apple Hardware Test software can be downloaded from the CD Images page on AppleCare Service Source go to the Service Source home page...

Thermal Pad Replacement Instructions

Whenever the logic board is separated from the bottom housing, you must install new thermal pads to three 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 ,...

Display

LED on the display bezel does not light up Note The LED does not light up when the power is on however, the LED should pulse when the computer is in Sleep mode. 1. Put the computer into Sleep mode. Does the LED pulse now If yes, there is nothing wrong with the LED. If no, replace the display bezel 922-5297 . The LED is attached to the display bezel and cannot be ordered separately. Screen tilts to the left or the right even after a manual adjustment. Note It is normal for the screen on an iMac...

Diagnostic Test Points

The iMac 17-inch Flat Panel has four test points and one ground pad on the bottom of the logic board. These test points are accessible under the customer access panel via two small cutouts in the plastic shielding see below . These test points provide an easy troubleshooting tool for common problems. To use each test point, put the positive probe of your voltmeter on the test point, and the negative probe on the ground pad.

Resetting the PMU on the Logic Board

Resetting the PMU Power Management Unit on the logic board can resolve many system problems. Whenever you have a unit that fails to power up, you should follow this procedure before replacing any modules. 2. Remove the user access panel from the bottom of the computer. 3. Press the PMU reset switch shown below once on the bottom side of the logic board and then proceed to step 3. Do NOT press the PMU reset switch a second time because it could crash the PMU chip. 3. Press the PMU reset switch...

Procedure

Tmds Connector Imac

Remove the four screws connecting the fan bracket to the chassis Faraday cage . 2. Lift the fan bracket from the chassis. Note The fan gasket is stuck to the back side of the fan bracket. Replacement Note For reassembly, note the orientation of the neck cables see below in the fan bracket Blue Blind Mate Connector cable Green Blind Mate Connector cable 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...

Whats New and Different

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. 2. The LED and microphone are part of the display bezel 922-5297 they cannot be ordered separately. 3. The LED functions differently on the iMac 17-inch Flat Panel . The LED does not light up when...