Introduction This chapter is designed to highlight unique or high- priority product issues that you should be aware of before servicing the iMac computer.
This chapter alerts you to important issues and provides pointers to other areas in the manual where more complete information can be found. This chapter is not intended to replace other parts of this manual; it merely provides a pointer to pertinent information in those chapters.
To familiarize yourself with a new product family, always read the Basics chapter in its entirety. You should also refer to the Troubleshooting chapter for basic theory of operations information. Hot Issues Mixed Memory Types - 2
Mixed Memory Types The iMac computer uses SDRAM SO-DIMMs only; EDO memory will not work in the iMac computer. System problems will result if EDO memory is installed. (See "SDRAM DIMMs" in the Basics chapter and refer to the iMac section of the Memory Guide.)
Note: Customers are allowed to upgrade the memory in iMac computers and may inadvertently mix EDO and SDRAM memory. If incompatible memory types are installed, you will hear two beeps upon startup. (See "Power-On Self Test" in Troubleshooting for more information.) Hot Issues Mixed Memory Types - 3
SGRAM Video Memory The iMac computers use SGRAM video memory. Use only SGRAM SO-DIMMs in these machines. Never install the 256K or 512K video memory DIMMs used in older Macintosh computers. (See "SGRAM Video Memory" in the Basics chapter.)
Error Beeps If problems are detected upon startup, the iMac system will sound one or more error beeps. (See "Error Beeps" in the Troubleshooting chapter.) Hot Issues HFS Plus Formatted Drives - 4
HFS Plus Formatted Drives The iMac hard drive is formatted from the factory with Mac OS Extended format, also referred to as HFS Plus. Norton Utilities version 3.5 is not compatible with HFS Plus and version 3.5.1 and earlier can result in hard drive corruption and loss of all data on the hard drive. (See "HFS Plus Formatted Drives" in the Troubleshooting chapter.) Hot Issues Forcing a Restart - 5
Forcing a Restart If holding down the Command, Control, and Power keys fails to restart the iMac computer after a system hang, you can force a restart in one of two ways:
First, try inserting a straightened paper clip in the reset button hole. (Open the I/O door on the side of the iMac. The reset button hole is the top hole located between the Ethernet and modem ports and marked with a triangle symbol.)
If the reset button method doesn't work, try the following: 1. Unplug the power cord. 2. Wait at least 30 seconds and then reconnect the power cord. 3. Restart the iMac by pressing the power button on either the keyboard or the front of the computer. Hot Issues External Displays Not Supported - 6
External Displays Not Supported Connecting an external display to the iMac is not supported by Apple. The db-15 port on the iMac was not designed to support an external monitor. Apple designed iMac with a very sharp, 15-inch internal display and no video-out port to connect a second display.
Refer to Tech Info Library (TIL) article #43016, "iMac: Can I Attach an External Display?" for more information. Hot Issues iMac Updates - 7
iMac Updates Apple has released a number of updates for the iMac. Refer to TIL article #58174, iMac: When to Install Available Updaters. This TIL article will clarify when to use the available updates depending upon which version of iMac you have.