PowerBook G4 slow fans

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.

eyoungren said:

Some thoughts…

What browser are you using and what type of sites are you typically visiting? PowerPC Macs are great, but the type of browser you use and the sites you visit can affect heat. For instance, using stock Safari and watching a lot of YouTube videos can send the processor into 100% CPU territory and keep it there. That kind of thing provokes heat.

So, if you have not investigated other browsers or other means for flash video I might look into that. TenFourFox is a great alternative to Safari. Right now the stable version is at 17 which is the equivalent to Firefox 17 and the unstable version is 24, equivalent to Firefox 24. TenFourFox is updated regularly (24.2 beta just released yesterday) and is secure.

Leopard Webkit is based on the nightly builds of Safari and is also a great alternative as it makes Safari secure.

There's also at least two apps that will play YouTube in a seperate application. The names escape me at the moment but someone can probably suggest them.

Back to the heat. 140º is actually a normal range. Yes, the fans come on, but if you are doing any browsing you can expect that the Mac will hit 140º at some point and then cool down. My 17" PowerMac G4 1.0Ghz does this ALL the time. The fans will NOT spin any higher than is necessary to cool the Mac down below 140º and then will shut off. If you hit higher temperatures such as say 145º+ then the second fan will kick in. The second fan operates at a much higher RPM and will shut off once a range is reached that the first fan can handle.

I understand that you are saying the fans are only reaching a certain speed and that does seem a little slow compared to the RPMs on my 17" PowerBook, but that may just be the speed that's set for your PowerBook. As long as your Mac is being cooled down then it shouldn't matter. Check the CPU with iStat Menus when you are browing. If it's constantly pegged at 100% then this is why the fans are on, because heat is ocurring.

As to this being not normal to you when the power is plugged in, there also may be an issue here. Open System Profiler with the power cord plugged in. Under Power, check and see if the adapter is delivering 65W. If it's not, you have a faulty power adapter. Most of the Aluminum Powerbooks require 65W and power adapters delivering less can really cause unusual things. Over time it can cause damage. If it is delivering 65W and this still seems an issue to you (no CPU spikes and such) is there anything else? Does the power cord wobble in the connection? Do you have to move it at all to make sure power is being drawn? If so, you could have a faulty DC-In board. That could also affect things.

Let us know.

Click to expand...

I checked everything you said, and found that everything was normal with power, system health and performance. I downloaded G4FanControl and set the minimum values for each sensor several degrees lower than what they were set at. Now my machine runs much cooler (although slightly louder), and the fans actually run at over 1000RPM under load. I'm fairly happy with the results.

Now, one last question: do these settings remain in firmware/PMU? As in, if I reinstall the OS, wipe the disk, or decide to put 10.4 on this G4, will these settings stay with the system, or will I have to redownload G4FC and set these minimum temps each time I install an OS? If I do, it's no big deal. Just wanted to know.

By the way, I checked online, and found a bevy of G4 fan problems kind of like mine. Apparently, 60º C is normal operating temperature for a G4, and the fans aren't supposed to kick in much except to drop the temps back below 60 (especially on the 15.2" models). Crazy Apple.

I've attached some pictures for the full effect.

Yeah I figured... guess it was too much to expect.

I'm actually using the old 0.4 version of G4FC, the one without a GUI. Yes, I know, I'm crazy, but I'm an old-time Unix hacker so I was right at home.

I rebooted and the settings didn't persist, but it was pretty easy to write a quick and dirty shell script to put into Login Items, so that every time the computer boots, it resets the fan control settings to the user-defined ones. Also, the 0.4 version of G4FC, oddly, has worked on practically every PowerBook I've tried it out on, unlike the paid version.

Inspired by this idea, I've set out to actually build an app that does this for you and uses G4FC 0.4 as its core; essentially, I'm building a frontend to the command-line version of G4FC. Also a nice bonus: if you really want to cool your PowerBook down quick, I've added a "Turbo Cool" button that changes the minimum temps for fans to kick in to 20º C so that they run at full speed for a user-specified time, and then swaps them back for normal values.

It should be finished in about a week. Stay tuned!