Apple iMac (17-inch Mid 2006) - Manual (Page 122)

iMac (17-inch Mid 2006/Late 2006 CD) Troubleshooting — General Info 122
General Information
Serial Number
iMac serial number is located on the bottom of the computer stand.
Power On Self Test (POST)
Intel-based Mac computers rely on a combination of tones and blinking LEDs to display Power
On Self Test (POST) error codes.
If the computer detects out-of-specification or no SDRAM or the RAM installed does not
meet the appropriate specifications, the screen will remain black but the power LED on the
front of the computer will blink once per second to signal the error. This error condition may
be due to physically damaged RAM, installing the incorrect type of RAM, or not having RAM
installed.
Some RAM may appear to pass the Power-On-Self-Test (POST) but still cannot be used by the
operating system. In this case, the computer will display a gray screen, sound three tones and
blink the power LED on the front of the computer three times, pause, and repeat the blinking
until the computer is turned off.
The solution to both of these situations is to first re-seat the memory and test the computer
again. If the memory fails the POST test again, try memory that has been verified to work
correctly on another system (i.e., “known-good”) or order new memory. •
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