Having used Intel Macs all my life, I decided it was time to experience a PowerPC Mac. I traversed eBay for a good condition PowerBook, and found a great deal on an A1106 1.67 G4 with no scratches or dents. It even came with the original power cord, all for only $89 without shipping! I got it in 4 days, and boy, does this thing fly with 10.5 on it. I decided to see how long I could survive in a web browser, so I bought a new replacement off-brand battery, and I was back in business with a respectable 3.5 hour battery life. While using the notebook for day-to-day tasks, I nearly never miss my MacBook Air, but when I'm using it plugged in, a puzzling problem begins to arise. For some reason, the fans just seem unable to cool down the computer. Whenever I'm plugged in, the temperature just skyrockets to over 140º F. Now, I've seen from many others that the nominal RPM range for the PowerBook fans are from 0-9000RPM, but at scaldingly hot temperatures, my PowerBook stays at 140-142º F even when doing light tasks such as browsing the web with plugins disabled. With many complaining about loud PB fans, I wondered why my G4's fans were noticeably quieter than even my MacBook Air's. To figure out the problem, I downloaded iStat Pro, installed it, and felt my heart sink as I saw the fan speeds of the PowerBook stuck at 300-800RPM. It didn't matter how hot the notebook got, the fans would just refuse to spin at above 1K RPM. I tried resetting the PMU and PRAM both. No avail. I got a can of compressed air, turned the laptop on its front, and blew air into the vents and heard the fans spin up. No dust came out, but I booted the computer and launched several QuickTime videos downloaded from YouTube as a stress test. Still no avail. I don't know what to do at this point. The computer runs like a champ, but the temperature spikes are extremely worrying. Oddly enough, this seems to be exclusive to me running with the power cable connected. If I have the cable disconnected, temps stay extremely hot, but then return to normal after a restart. If I have the cable plugged in, but set CPU performance to "Low," regardless of whether I restart or not, the temperatures stay ludicrously hot. It's not a problem with the PSU either, because power supply temperatures consistently stay well below the CPU temperatures. I have a suspicion that this computer has been kept in a closet for most of its life and probably has fans caked with dust. However, I could hear the spinup on both when I blew compressed air into the vents. Apart from that, it's a great computer. Any fixes, solutions, or suggestions? EDIT: For those who don't know me, I'm MR member "kunai." I lost my password for my original account, and had long-deleted the email associated with it, so had to sign up for a new account.