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Intel-based Mac computers such as the iMac rely on a combination of tones to indicate Power On Self Test (POST) error codes. • If the computer detects out-of-specification or no SDRAM, the screen will remain black but the computer will beep. This error condition may be due to physically damaged RAM, installing 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 repeat tones until computer is turned off. • The solution to both of these situations is to first re-seat memory and test computer again. If memory fails POST again, remove all installed memory and test by installing one by one each memory module that has been verified to work correctly on another system (i.e., “known-good”) or order new memory. • A sequence of tones heard at startup or a no video symptom may also be fixed by ...

The System Management Controller (SMC) is a chip on logic board that controls all power functions. If computer is experiencing any power issue, such as not starting up, not displaying video, sleep issues, or fan noise issues, resetting SMC may resolve it. To reset SMC on an iMac: 1. From Apple menu, choose Shut Down (or if the computer is not responding, hold power button for approximately ten seconds until it powers off). 2. Unplug all cables from computer, including power cord. 3. Press and hold the power button for 5 seconds. 4. Release the power button. 5. Attach the computer’s power cable, making sure power button is not being pressed. Note: If you press the power button while inserting the power cord, the iMac will enter a mode in which the fans run at full speed. 6. Press the power button to turn on the computer.

PRAM stores certain system and device settings in a location that Mac OS X can access quickly. Exactly which settings are stored in the computer’s PRAM varies depending on the type of computer as well as the types of devices and drives connected. To reset PRAM: 1. Shut down the computer. 2. Locate the following keys on keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in Step 4. Note: If the keyboard does not have an Option key, use the Alt key instead. 3. Press power button. 4. Immediately press and hold Command-Option-P-R keys. Important: You must press this key combination before the gray screen appears. 5. Hold down keys until the computer restarts, and you hear the startup chime a second time. 6. Release keys. if you still have problems call us +1-855-517-2433

Starting up into Safe Mode does several things that can help resolve software or directory issues that may exist on the startup volume. To start up in Safe Mode: 1. Shut down the computer. 2. Press power button. 3. Immediately after you hear startup tone, press and hold Shift key. Note: The Shift key should be held as soon as possible after startup tone but not before. 4. Release Shift key when you see the screen with a gray Apple and progress indicator (looks like a spinning gear). Note that booting into Safe Mode will take longer than a normal startup. During startup, the words ”Safe Boot” will appear on Mac OS X startup screen. 5. To leave Safe Mode, restart computer normally, without holding down any keys during startup.