Sunday, November 23, 2008

MDD Mania

It's been several years since I last posted to this blog - I blame Life, The Universe, and Everything, naturally. I was sitting on several posts on my quest to improve on my MDD G4's thermal and noise output but I don't remember if they're either all back on the MDD in Toronto or if they got lost in the mists of time.


I could be verbose with another lengthy set of posts, but here's the long and the short of the other modifications I did to my MDD:

Dual Front 60 mm Fans:

When I was cleaning out my MDD of dust I truly began to get an appreciation for how the MDD's cooling system was designed - like past Power Mac designs, in the MDD air is drawn from beneath the computer and into the interior to cool the components inside. Unlike past Power Macs however, the majority of the air is drawn from a cavity cleverly concealed underneath the front panel, not through the four front holes as you might expect. This cavity is lodged between the rear surface of the front panel, the case itself, and the bottom front handle, and pictures of an MDD cooling mod on illustrates this well. Obviously, this means that airflow isn't very efficient. To aid things, I found two generic Chinese-made 60 x 60 x 20 mm fans (from a surplus computer parts store near Bloor and Bathurst in Toronto) and screwed them to the perforated sheet metal of the case which covers the large oval air intake. It's just like the mod I highlighted earlier on bitsandpieces, only with narrower fans so that I wouldn't have to change the superstructure of the case, hack the plastic panelling, or remove the front hard drive carrier. To reduce noise from vibration I used rubber O-rings normally used in plubming from a local Home Hardware store. To additionally reduce noise, I hooked up both of the fans to an (admittedly overpriced) Nexus fan speed regulator cable purchased from InMax Computer (a 3-pin to 3-pin cable with several resistors in the middle, from the looks of things).

Dual Rear 60 mm Fans:

I never gave up on replicating Steve Smedley's original mod of attaching two 60 mm fans to the perforated grille behind the CPU heatsink; I realized that I needed to get thinner 60 mm fans, but where? I then realized that I knew two stores all along which had just the right parts I needed: Active Surplus on Queen Street, and the store I mentioned earlier whose name seems to escape me at the moment.

Using the same setup as the front fans, the fans installed (for the most part - getting the fans positioned in the right place is tricky work) and work just fine. The last time I was in Toronto however, I noticed a loud buzzing noise from my computer. It seems that one of the fans I put back there is on its last legs - I'm not relishing the arduous task of taking the fan out and putting a replacement in.

Noise Dampening Foam:

To help minimize the noise from all of the fans I've put into this machine, I liberally applied special noise dampening foam all throughout the interior of the machine, or at least, what I could find that was bare metal. The foam itself resembles something you might get at an aquarium, or the sort of foam you get as weatherstripping for windows - except that it comes in adhesive sheets. At the very least, it should minimize noise from potential resonance effects from the exposed bare metal surfaces on the inside of the machine. I found that it had the most effect when used on metal-to-metal joints.

PCI Slot Cooler:

Looking at the interior of the MDD hints at one potential problem from the internal organization of the internal components - while air is being brought into the bottom of the case, the optical drive bays and PCI cards get in the way from any of that fresher cooler air from reaching the PSU. Sadly, that may not have been an issue for me had those @#$%^& ~60 mm aluminum fans fit into the PSU front the way that they should have.

Turns out that there's an interesting product that seemed to be just what I needed - companies like StarTech or Ultra sell (or at least used to sell) a PCI slot cooler which is more than just a ducted fan bolted onto a PCI slot cover. Instead it has two smaller 5 cm fans on extendable "turrets" which rotate 180ยบ. You can even unscrew them and mount them backwards to blow air inward instead of sucking air out (which is what I eventually did). I was somewhat concerned that with airflow being as poor as it was I may have just been sucking hot air that was being blown out right back into the machine, but I haven't seen any major problems since I installed it. At least the air on the outside of the machine being sucked inward will be somewhat cooler than the air being blown out.

USB "Moving Soundcard":

While rummaging around for various stuff to shove into my Mac at InMax, I noticed a most curious device - a "USB moving sound card". Made by Chinese manufacturer Comodow, it was the PD-552, a teeny-tiny USB 2.0 device with a mic-in port (not the same as the line-in port on Macs, which is incompatible with standard PC microphones) and a headphone/speaker jack. There was no driver disk, and not even any mention of OS support. I'd never been so uncertain of an upgrade before, but I bought it on a hunch that if it conformed to the USB spec., the Mac OS should at least detect it. Lo and behold, it worked, and worked pretty darn well with the Audio MIDI Setup application included with 10.4. It even worked with 9.2.2 as well. Eventually, I transferred it to my mother's older Sawtooth, and instead used a similar sound card with volume control buttons that suprisingly mimicked the volume keys on my standard Apple Pro Keyboard.

Rounding it out were some other less-tangible extra upgrades - aluminum heatspreaders for my DDR RAM modules (not an unreasonable thing to do, given that the motherboard design shoves the RAM slots between the two main sources of heat generation on the motherboard: the processor and the video card), and plastic tubing to neatly wrap up the power connectors all over my motherboard. Thermaltake used to sell an interesting active cooling solution for memory which included not only heatspreaders but a small 40 mm fan to actually blow air on the memory modules. I'd considered actually using that until I saw that reviews found its effectiveness dubious at best.

Last but not least was a monstrous shot in the arm in the form of a 128 MB GeForce 4Ti, once the king of graphics cards on the Mac - I have Steve Smedley to thank for his generosity in having given me this fine card.

So, in a (admittedly rather large) nutshell, that's where my beloved MDD is right now, still going strong after all of these years.

Next up: My attempt at a comprehensive guide to USB cards on the Mac.


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