Editing Power Mac G4 (section)

== PCI Graphics ==
The first G4 tower, which Low End Mac calls the "Yikes!" model, used a modified blue and white G3 logic board with PCI video.<ref name="lemsaw" /> It differs from every later G4 in ways that matter for repair (pp. 207, 212–219, 239):<ref name="ss" />
* It has a Cuda microcontroller with its own reset button beside the battery, not a PMU. Apple's board reset for this model is to unplug it, press the front power button, take out the battery for at least ten minutes, and refit it the right way round.
* Its processor module needs a jumper block at J25 of the right colour for the processor fitted, with all its inner metal clips, the right way round; without it the machine does not boot. Apple supplies the block with a replacement logic board and warranty sticker (076-0760 for 350 MHz, 076-0758 for 400 MHz).
* Seven diagnostic LEDs on the board (DS1, DS4–DS9) show ATA activity, USB power, Ultra ATA activity, power and processor bus requests.
* Four or five beeps at start-up mean a bad boot ROM checksum.
Apple's parts for it are logic board 661-2253 and power supply 661-2256, the same supply number as the AGP Graphics model (pp. 276, 291).<ref name="ss" />