Mac Troubleshooting: PowerMac G4 667 (Graphite) and Resetting G4 PMU
Based on the Power Macintosh G3 (Blue & White) case design the PowerMac G4 677. This version of the PowerMac G4 differed from its predecessors not only in its processor but that it offered Digitial Audio and shipped with the first version to the DVD-R/CD-RW “SuperDrive”. Equipped with a 677 Mhz PowerPC processor with a AltiVec velocity vector processing unit, 256k level 2 cache, and 1 MB of backside cache. It shipped with 256 MB of RAM, expandable to 1GB, a 4x AGP NVIDA GeForce 2 MX graphics card with 32 MB of SDRAM, and available with AirPort (802.11b).
Apple produced two different series of its Power Macintosh G4 using two different logic boards. Highlighted in red is where the PMU (Power Management Unit) or Cuda Switch is located on a this 677 MHz PowerMac G4. It is usually in between the processor and the system battery on the mother board. To reset the G4 PMU follow these instructions. DO NOT RESET IT IF THE COMPUTER IS ON!!!