Apple Service Source manuals

online; but now they are gone An Apple ftp site has the Service Source manuals for virtually all of Apple's products (thanks, Larry Kahan). These manuals have "take apart" and troubleshooting repair information. They are targeted for service providers, not end users. As such, some of the procedures are clearly beyond the skills of the typical user - and you may void your warranty if you try them. Still, these manuals are a gold mine of troubleshooting nuggets that can be enlightening simply to read. For example, in the iMac (slot-loading) manual, I learned that there is a new PMU Reset button:

The PMU (Power Management Unit) is a microcontroller chip that controls all power functions for the computer. The PMU is a computer within a computer. It has memory, software, firmware, I/O, two crystals, and a CPU. Its function is to: • Tell the computer to turn on, turn off, sleep, wake, idle, etc. • Manage system resets fromvarious commands. • Maintain parameter RAM (PRAM). • Manage the real-time clock.

Resetting the PMU (Power Management Unit) on the logic board can resolve many system problems, such as failure to power up, no video on power up or a gray screen on power up.

Unfortunately, to access this button, you need to take apart the iMac and get to the logic board.

Update: Alas, the link above no longer works. My guess is that Apple does not want these manuals to be widely available and so pulled the "page" after they discovered that the link had been posted here. I am not surprised. In the future, you'll have better luck finding this stuff on your own. Any links that I post will get changed by Apple.