A quiet iMac DV

A couple of years ago, as fallout from a layoff, I found myself with a pair of 400 MHz iMac DV machines (“grape” and “blueberry”, for those keeping score). One of these sits under my desk, running software that will likely be illegal soon. The other has been deployed in the kitchen (more on that in a later entry).

As this model was discontinued in mid 2000, these machines were starting to show their age. They had a number of problems that I vowed to handle when I got around to it. I happened to get around to it late in 2004, but only after spending a great deal of time tracking some information down. This post intends to distill this information into one place for those looking to do similar things. (I found many such people asking for help, and not getting answers). The problems to solve were these:

  1. Intermittent video problems
  2. Intermittent boot problems
  3. Inability to turn off the internal monitor and use only the external VGA connection.
  4. Limited disk space
  5. Noise

It turns out that the first two problems are related. Earlier iMacs had a number of problems with their firmware and analog video boards conspiring in ways that manifest in random naughtiness. I’d seen several variations of the behavior on these two machines. Sometimes the internal monitor would not work at all. Sometimes it would display only very faintly or all in green. Sometimes a reboot would get past the boot chime and then die. The blueberry machine provided the drive to fix these machines when it started exhibiting the latter behavior all of the time. The grape machine could boot, but seemed locked in “dim display” mode.

After far too long searching for fixes to this problem, I happened across a link to an incredible troubleshooting page for this exact problem. Why this didn’t show up first (or even in the first few pages) in a Google search, I don’t know. Hopefully it does by now. In any case, this explained the problem and provided some great things to try.

According to this page, these problems result from old firmware, and the trick is to get the machine to boot long enough to upgrade it. This presented me with a problem. Supposedly, you cannot run OS X on this model unless the firmware has been upgraded to the latest version, the same version that fixes the problems. Having run OS X on these machines since the 10.0 beta, I assumed I had the correct version, but still had the problem. The machine I could still boot showed the latest 4.1.9 firmware version, but still had the dim display.

Thinking I was probably in for disappointment, I tried the troubleshooting tips with the blueberry machine anyway. I had what the page called “symptom S4”. I found that the older version of the page was a little easier to follow, but neither it nor the current version actually solved my problem. I ran through the firmware page up to and including the “intermediate” section, without improvement (though it turned out I had to replace the battery, so that probably helped some). Not thrilled about exposing myself to high voltage, I tried a few other things before moving into the “advanced” section.

I was under the impression that the extra power draw from the hard-drive spinning up was overwhelming the power supply. To test this, I pulled the power of the hard drive (the white plug with red, black and yellow wires coming out of it) and tried booting from an OS 9.1 CD. This worked fine (though, of course, no hard drive mounted).

I shut the machine down and, just for fun, reconnected the hard-drive power. And what do you know, the thing rebooted just fine. It may be that having booting it in 9.1 or, perhaps, just the change in hardware configuration managed to reset the PMU or something. Not sure. In any case, if you have nimble fingers, you can actually do this through the RAM access slot without taking the machine apart.

Once I got the machine to boot, lo and behold, it’s firmware version shows as 4.1.7. How I got OS X on this box in the first place, I do not know. Such a thing is supposedly “impossible”. Upgrading it to 4.1.9, however, turned out to be easier said than done. This is because the 4.1.9 updater only runs when booted into OS 9 from a writable volume. Since I didn’t run classic on this box (didn’t want to spend the disk space) and booting from a CD wouldn’t work (not a writable volume), I didn’t have a writable OS 9 boot disk. Further, something in the OS 9 install CD just refused to recognize the machine’s disk as one that could handle OS 9. After trying a whole bunch of weird Firewire setups, my problem suddenly resolved itself when the OS 9 installer started working for no evident reason. I have no idea why this happened but, once done, the firmware upgrade worked fine, and did solve the boot problem.

This left the dim display on the grape machine. It had the correct firmware, but still had the problem. Changing the contrast and brightness didn’t help. On a forum, I spotted a solution so obvious I can’t believe it took me so long to try it. All I had to do was go into the Display preference panel, go to the Color section and hit the Calibrate button. This process ended up resetting the display just fine.

So, two problems (including the biggest one) down, three to go. I still have found no solution for turning off the internal monitor while leaving the external port active. I suspect that I might be able just to cut the power to it, but haven’t found the schematics for it. If you know how, let me know. I’m fairly certain that there is no purely software way to do this.

The last two problems also turned out to be related. The iMac DV has no internal fan, so nearly all of the noise it generates comes from its hard drive. If you haven’t had the pleasure, the sound isn’t a typical computer hum, but more of a whine. It’s the type of sound that still thrums in your ears once it stops. So, finding a high(er) capacity, quiet hard drive seemed the obvious solution.

It turns out, this was less than obvious. In the first place, finding what kind of drives the iMac DV could support was a bit of an exercise in futility. Unlike most Macs before it, the iMac used IDE drives, not SCSI. All the information I could find was found in crumbs in forums, mostly unconfirmed rumors:

  • Rumor 1: Drives faster than 5,400RPM overheat the iMac DV. I’m not sure if this is true, but I believe it. The 4,200RPM drive that shipped with it ran the machine hot enough, with no internal fan. So, this set a spindle limit, which turned out to limit the drive selection significantly, as most higher capacity drives are faster than this.
  • Rumor 2: Drives larger than 128GB cannot be read iMac DV. I suspect this is just plain wrong, but saw it mentioned more than once. This seems like it would be more of an OS limitation, so might have been true once. I seriously doubt it is true now. I turned out to be moot in my case, because drives larger than 128GB went over my price target.
  • Rumor 3: The OS must reside on the first 4GB of a disk for the iMac DV. This is almost certainly false, considering that a) even the old, loud drive was a 10GB in a single partition and b) it doesn’t make any sense. I ignored this rumor, so far with no ill effects.

So, I was looking for a 5,400RPM IDE drive of 128MB or less. And it had to be quiet, which led to the next problem: what’s quiet for a drive and how do you find out? After some looking, I found Hardware Central, which not only lists the sound output of hard-drives in decibels, but has excellent search filtering as well. Sifting through the various choices was more annoying than it needed to be, but I settled on the 120 GB Maxtor DiamondMax 16. At the time, Tiger Direct sold these for the lowest price, around $70.

I bought one for each machine. They installed easily (well, as easily as a drive can be installed into an iMac), work great and are nearly inaudible. They do run a bit hotter than the old drives, but so far, so good.

7 thoughts to “A quiet iMac DV”

  1. Hi, Went through much of the above however when I installed the new internal drive the iMac would not start. It would hang on the OS X Apple Logo. I tried target disk mode and the drive showed up just fine that way. I reformatted it via TDM and installed OS X and 9 but upon a normal reboot it did the same thing. I was concerned that it might be a jumper setting problem and I tried all of them I believe. The drive is a new 40 Gig WD caviar. I checked the RAM chips and zapped the pram as well. Finally I reinstalled the old drive and the iMac fired right up. The whine is driving me crazy but I don’t know what else to try. Any suggestions?
    Thanks… Farcus

  2. Farcus, you don’t mention if you’re up to date on your firmware, but I know if you’re not up to date, you won’t be able to boot in to X. The other thing that I’ve heard other people having success with is booting into open firmware (with new drive installed, with OS X install CD in the drive) and performing the following series of commands:


    After the “reset-all” your machine should restart (if not, you can type mac-boot). Then try booting from the CD and running the installer. More on open firmware can be found at: http://developer.apple.com/technotes/tn/tn1061.html

    HTH… – j e f f

  3. Regarding rumor #1, “Drives faster than 5,400RPM overheat the iMac DV”. . .

    I just got done installing a 80 Gb, 7200 rpm hard disk into my iMac G3 400Mhz (mine’s raspberry) when I found your blog. I’m hoping that this rumor doesn’t turn out to be true! I guess since it’s up and running (and installing OS X as I type) I shall find out if heat is really an issue.

    If I do end up having heat problems, do you know some warning signs I should look out for? What will the excess heat kill first, the hard disk or processor?


  4. I checked the Apple website regarding the Rumor #3 about OS contained in first 8 GB of HD. This does not apply in this case since we’re talking about an iMac DV Special Edition 400 MHz. This iMac doesn’t have these limits. And also you can clone your internal HD into an external one, and boot from the external one. If it works, it would be a breeze since you can clone it back to the new HD.

  5. Big problem.
    Something strange happened to me yesterday, I tried to upgrade my girlfriends Imac dv. with a 512Mb ram added, and a very silent Samsung 7200 80 mb H.D.
    At first installing OsX panther seemed to work all right, then when the installer asked for the 2nd. disk, the problems started. The Mac should throw out the first cd , and reboot and continue to install. However, after the booting doing sound, everithing went silent, and the mac was just doing nothing at all. After a lot of trial and error, I found out, that keeping the start button pressed, and waiting for a rather unpleasant sound, a Dos-like screen appeared, and told me if I wanted to I could boot by typing mac-boot. this worked fine. In the end I had a well installed OSx, but there was no way the Mac would boot in a normal way, only by performing the procedure mentioned above.
    Installing OS9 on the separate partition made things worse, I was not able to choose the disk to boot from, and got stuck with Os9, that ‘s not what i intended in the first place.
    So I took out the Samsung disk, and built in the old disk with Os9, than I was more than flabberghasted, to find the old disk behaving the same way as the new Samsung, not way to boot it normal, only by means of that command mac-boot.
    I replaced the Pram battery, made sure the firmware was o.k. Checked the bew inserted RAM. What o what should i do.
    A desparate Dutchie.

  6. As no real harm could be done, I applied the procedure mentioned above,

    !!problem solved!! Thanks Jeff.

    B.T.W. anybody knoes if my newly bought RAMis really nv? Or was it all just a mishap during installation of OSX?

  7. I’ve had a fast PC HD in my iMac DV for months, it does get quite hot and has had some issues we think are heat-related (like kernel panics in OS X), but it’s not bad unless the temp outside is great. We keep a fan on it on those hot days and all is well.

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