That is true. But in this thread, the CPU in question is a 500 MHZ OWC G4. Looking at the OWC Site it doesn't seem these were shipped with special heat sink, the installation instructions say to use you old one, (in both the beige, the B&W (which have a smaller heat-sink) than the system here (The G4 with the larger heat-sink). I saw this once before on an intel PC. The user opted to continue to use the computer after the CPU fan failed. At some point the chip stressed and stopped working. Even after replacing the fan the cpu could no longer operate at its "rated" speed but would operate at a lower one. I don't know why that eluded me when I was looking at this from the start. I should have done this first thing. Lower to the clock speed to the lowest the board would allow and see if I could get the video up.
Thanks! Gus. On Aug 6, 4:42 pm, Clark Martin <[email protected]> wrote: > On 8/6/10 1:48 PM, Gus wrote: > > > The Short Answer: Yes a bad cpu can give you a good Power On Self > > Test Chime. What you do is keep downclocking the CPU till it > > eventually gives you video and boots. You may even have to go to the > > lowest setting your motherboard allows before it does gives video and > > boots. If a CPU has been heat stressed in the past, it may say that > > it is a 500 MHZ processor, but may work just long enough to pass the > > P.O.S.T. and give a chime, and then lock up (at its 500 MHZ > > settings). Lower clock speed = less heat = more likely to boot. > > It's not just a matter of heat. The chip may just not be able to run at > a given speed regardless of how hot it gets doing it. > > One suggestion, keep dropping the clock speed till it boots and works > okay... then drop it one more. You may be right on the edge of it > working okay and any little thing could push it over such as temperature. > > -- > Clark Martin > Redwood City, CA, USA > Macintosh / Internet Consulting > > "I'm a designated driver on the Information Super Highway" -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list
