Unwelcome Mac noises

G3 Macs Bruce Kieffer complains that: "I randomly (maybe once a week) hear loud, short, screeching noises coming from what appears to be the internal hard drive of my G3 Mac. It sounds like glass breaking." He notes that, on Apple's Power Mac Discussion Board, other users have reported similar noises.

Actually, avariety of noise-related issues have been posted to the Board. For example, one user wrote that his G3 Mac occasionally "makes a brief harsh rhythmic grating noise. During the noise, the system freezes. Since this noise is very brief and relatively rare it does not significantly interfere with operation of the computer. After it ceases the system operates normally." Another reader offered the explanation for ths noise: "I called Apple with a similar question about my G3-266 tower. It appears that the sound comes from a vibration in the shielding of the case when the CD-ROM is active. Apparently, the 24X CD-ROM doesn't continually spin, but shuts down frequently. Therefore, when it starts up again the vibration increases and the Finder is not as responsive. The technicians response was to suggest that I have the case looked at, but nothing can be done with the way the 24X CD-ROM works."

7300/7500/7600 noise: redux Finally, speaking of noises, I am reminded of the high-pitched whining noise reported to occur after upgrading the CPU on some Power Mac 7500s (and possibly other first generation PCI Mac models). This was discussed on MacFixIt months ago. Apple never offered any explanation, as I recall, although other sources pointed to a problem with the power supply - and that a grounding clip might be needed to solve the problem. In that regard, I found it interesting that there is a TIL file (#24186) that mentions possibly needing a grounding clip when upgrading a 7300/7500/7600 to a Power Macintosh 233-MHz Processor. A clip is included with Apple's Upgrade Kit. (Thanks, Monroe Williams.)