Assembly

Heatsink

FW/USB2 Card and Reset Switch

Finished Product

Fans and VGA Cooler

Details of the Conversion

The Tear Down


I had originally thought of just getting a digital audio mother board, but in the end got a whole system. In the end this worked out for the best. I purchased a complete Digital Audio machine, then stripped out the Motherboard, PSU, Power Board, and Ribbons/Cables.


The Layout

Mounting the Motherboard wasn't going to be as easy as most ATX conversions that get done do to the way the G5 case is constructed. Being unable to drill holes for standoffs, I had to take another approach. I pulled out all but a few of the original G5 standoffs which are pressed into recessed cutouts. There is four types of standoffs used in the G5, two lengths that have balls on the top, and two lengths with screw holes machined into them. To get the height of the DA board correct, I used the longer of the two standoffs with screw holes. These turned out to be perfect. To attach them to the G5 case, I ended up using Super Glue Gel. I had originally thought of using some electrically conductive epoxy to attach them, and get a case ground at the same time. But the only electrically conductive epoxy I could find was silver based. With the case and standoffs being aluminum, this would have caused some electrolysis problems between the two metals. To get a ground, I simple added a wire going from a ground on the board, to one of the existing G5 standoffs that I left just for this purpose. Do to the G5's only having three PCI slots, one of the DA's PCI slots was going to have to be left without a slot in the back of the case. The back of the G5 case had to be cut to allow for the different port layout of the DA, the upper shelf also had to be cut to leave room for the Motherboard, as the board goes up above this level. The hard drives where installed inside the original G5 drive carrier, but the drive carrier had to be moved do to the Motherboard stretching up above the upper shelf. The power supply also couldn't be in the normal location, so was moved down onto the floor of the case. Currently I am having to stretch the power cord into the case to plug into the supply. This is only temporary, until I can finish a power-plug for the rear of the case, to allow for an external power plug. For turning the machine on, I wired up the original G5 power switch to the power board that was in the DA.


Cooling

Thus far the machine runs MUCH cooler then it did while inside the original case. The processor currently has the stock OWC heatsink, this will be replaced with an Athlon heatsink and fan setup soon. The only case fan is a rear 80mm fan from an iMac rev/D which is hooked up to a rheostat to adjust the speed of the fan. It is currently running at a fairly low speed and makes minimal noise. The loudest fan in the machine once the OWC fan/heatsink is replaced will be the Radeon's fan, which makes a very distinct sound.

UPDATE: New heatsink has been modified to fit the OWC upgrade. The heatsink runs MUCH cooler then the original heatsink, and is quieter. It is a Jetway 'Heat Pipe'. Its basically two heatsinks with heat pipes connecting them. Thus far it is working very well. The fan is a 70mm, 3800rpm fan. It is also the only heatsink I have seen that blows sideways, so it helps with the airflow going from front to back.

UPDATE (12-09-04): Added two 92mm PanaFlo (FBA09A12L1A) fans to the rear of the case, replacing the old iMac fan. Not only do these fans run quieter then most fans on the market, they also put out a good deal of air (Max. air flow: 42.7 CFM. Max. noise: 27.0 dB-A @12VDC). I am currently running them at 9VDC, this makes them quieter, but still put out plenty of air. You can feel cool air moving into the front of the case with your hand. I also added an Arctic Cooling VGA Cooler Rev.3. This cooler is designed to cool R3xx series ATI video cards. It has two fan settings, both of which are quieter then the stock fan (which has the sound of a dremel). It intakes air from the case, and spits the warm air out the back of the case through the adjacent PCI slot.

UPDATE (12-11-04): I added a fan speed controller to the CPU fan, and now have it slowed down to about 2000rpm instead of 3500rpm. This has made the overall volume of the machine much quieter. While it is audible, it is not obnoxious at all. I sleep in the same room this machine is in, and have no trouble with leaving it running.

UPDATE (12-28-04): I have added a Firewire/USB2 combo card which has 3 FW ports, and 5 USB2 ports (for $15 USD). One FW and one USB2 port is located on the inside. I also have added a reset switch incase the machine locks up. It is accessable through one of the holes in the front grate.



Closing

Overall I am very pleased with the conversion. The machine runs quieter and cooler. While the case is limited to one internal Optical drive, it has room for two more hard drives if I have the need to add more in the future. I also plan on making the front ports functional in the future using a USB/FireWire card which has internal ports.

OK, the question of the day seems to be, where did I get such a case for less then several hundred dollars? Well, what I will say is I Have a source who was able to obtain a case which was deemed "defective" for a very minimal cost. The part which was defective was the Optical Drive door. This was an easy fix, for people who come across this problem, you can learn how to fix it HERE.

The second question I am being asked is if the front ports will eventually work, and yes, they will be functional once I get to that point, and it will be updated on here.

Another recent question which I have been asked several times is why this mod will not work with an MDD G4, and put simply, the board is backwards. If you laid one of these boards inside a G5 case, or any ATX style case, the first thing you will notice is that the PCI slots are on the wrong side. This makes it quite a bit more work to put one of these boards into a case besides the original case in came in. In order to install it into another case, the case would have to be reversed. By reversed, I mean put the backplane that the board mounts to on the opposite side of the case, and put the door on the other side of the case as well. Overall this could be quite a bit of work, and would involve some metal working tools most likely. I can see there being a market for such a case if somebody took the liberty to make one. Marathon Computer seems to like these kinds of products, as they make iMac conversions for both tray load and slot load styles.