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| Franken Mac G5 - Acrylic Case |
| Written by Dixon | ||||||||
| Tuesday, 31 January 2006 | ||||||||
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Franken Mac G5 1.8GHz
  Pictures are during testing/loading OS so lid isn't closed fully.
This project started when I was surfing on eBay looking for a good price on an iMac G5 for work. All of a sudden I noticed a seller selling an iMac G5 1.8GHz motherboard with PROCESSOR. After getting it for a decent price, I started to research the parts needed and the most challenging was the power supply. With NO previous build of this board on the web, mapping the pin outs on the power supply for a standard PC ATX power supply seemed daunting and "dangerous". Luckily for me, the seller of the motherboard had the power supply for sale also and I picked it up.
So with mother board and power supply in hand, I made a trip to a couple local PC computer stores and an Apple store to find the remaining parts. It's NOT a small board and there weren't many cases that would fit. I did notice with a little surgery, I could use a full size ATX tower or a media center case, but that seems pointless as it would be UGLY! In the end, I decided that a custom Acrylic box was the only way to go. A lot of thought and careful planning was needed before ordering a custom case. Not to mention, I should TEST this board to see if it even works. The minimum parts needed for the test:
Happily, the test worked and system profile showed I had all the goodies from a rev. B board. I didn't know at the time of buying if I had the rev A or the rev B board. Luckily it was the rev B. Just more reassuring that it was a more refined board and not a first generation.
With a basic case design in mind, I started to think about cooling and the orientation of things in the case plus cable management. With the motherboard facing UPWARDS, how was I going to route the cables.
I didn't want a case too tall or big so I started looking at solutions that would route the cables out the left side of the case. First thing I started scouring around for were cables that would plug in and have very little height. Basically 90 degree plugs. I needed 3 USB, 2 firewire, 1 network, one modem and audio/mic plugs. Thinking it would be easy to find, I discovered it wasn't! One electronics store gave me a great suggestion, and it turned out to be "retractable cables". The wires are highly flexible and THIN! I still needed to hit the web to find them all. Surprisingly, it was the USB 2.0 (lots of USB 1.1) cables that were the hardest to source for a reasonable price. I did find 90 degree plugs but they were very expensive (over $50 for three). Lastly was the power cord, but that was easily sourced at a electronics part supplier. As expected, half the online stores never delivered or delayed delivery. To the point that weeks later I'd walk into local computer stores and they were sitting on the shelves....doh!
Cooling This issue took the most thought and planning. It's also too soon to say if I'm happy with the results. I'll be monitoring it for the next few weeks to see if more exhaust holes will be needed in the case or adding another fan or two. When I got the board, I noticed two areas to plug in a fan. I picked up FOUR 80mm case fans at the PC store. Two clear with LED's and two standard black ones. For some reason I couldn't find a SILENT clear fan without the LED's. In the end, I decided on using the black models (Ultra 80mm silent series from TigerDirect @18dB) as the blue LED's are just too bright for my tastes and louder (22dB). The fan plugs on the board worked with standard 3 pin fans. The pins on the iMac G5 board aren't standard though, so I couldn't get the third pin working (controller). So the fans are always on. Luckily, they are REALLY quiet. Even when running, it's well below being an issue. Definitely quieter than my Mac mini when it's fans are on. The two fans have the airflow going into the box and a passive 2.25" exhaust hole where the cables go through. When the computer is on, you can definitely feel a slight breeze coming out of the cable hole. Early testing of the final box noted that the box was still getting too hot and would hit the thermal shut off point under VERY hard load. Remember this is a sealed box except for a 2.25" hole. I decided to get a Y-splitter for the fan and place a third fan inside the case to move the air around more around the power supply. This is a temporary position but it seems to have done the trick with the box not hitting the thermal shut off. Average temp on the CPU is about 50-70C (122-158F). This third fan most likely will be installed as an exhaust fan on the left side of the box, next to the cable hole.
early design with bolts to raise the drive off the mount. I used rubber spacers now The hard drive is the next heat generator and it's sitting above the board on an acrylic platform, mounted above the platform with 1/4" rubber spacers. The platform was screwed into the back banel of the case. Airflow can easily go above, below and around the drive. Still the drive gets hot under full load and I may install the fourth fan for the hard drives. Just have to find a QUIET one. The on board Hard Drive sensor cable is to far away from where I mounted the drive so i cannot use it to monitor. I'll have to see if there is an external solution.
the picture doesn't show, but everything is lined up straight The next thing to consider is the heat sink on the G5 processor. It has a pretty good heat sink on top of the G5 CPU, but I noticed a flat plate about 1"x1" under the board with thermal grease residue. From what I could gather off the web, there was a heat sink on the bottom also in the iMac G5 design. This led me to decide on getting something for the bottom also. I thought of aluminum. I ended up getting a 1/4" thick plate for the whole motherboard. This would act as a rigid mounting for the board and raised off with 3/8" spacers/standoffs. After the board was mounted on the plate, I wedged two smaller pieces of aluminum under the CPU to draw the heat into the plate. It seems to work great when I opened the box and felt the heat on the large plate around the CPU and the two wedged pieces. They were definitely warmer than the rest of the plate. I didn't tap and mount the plate to the acrylic case. I may still, but currently it is raised about 1/4" with four rubber discs. The power supply rests on the aluminum plate also so heat is transferred down. With two fans blowing it should take a lot to heat up the aluminum plate. When testing the temp by feel, it does get warm under full load but never hot. The power supply does get quite hot and it is probably the highest continual heat source in the box. I suspect the final design with have some exhaust vents/holes around the power supply. CASE design
Which leads us to the case. I thought of using retro cases like a Quadra 900/950 if I could source one. I thought it'd be cool to present it in a classic Mac. In the end, I wanted the lowest profile case possible hence the search for all the low profile cables. The acrylic box was ordered from a great local shop that I found off the web (Acra-Fab) after two cardboard mock ups. The interior volume is 12"x18.5"x4.5" There are 3 holes on the case (1 on the back panel and one on the right side and left side). The hole sizes are 2.25". The side and back fans feed the box with air and the 2nd fan on the back will exhaust air, plus a hole out the left side to fish all the connectors out. I was going to use front case ports but ended up not to minimize the clutter in the box. The retractable cables really made it possible to keep cable clutter to a minimum. For the case I used 3/8" fire polished Acrylic. I debated on the case and whether to glue the bottom and sides with a removable top (cleaner look) or to have removable panels and lots of screws. I ended up with glued sides and a removable top and back piece. The little things... Start up Button: Since all modern Mac keyboards do not have the start up button on the keyboard, I had to source out a 3rd party USB item. The start up button on the motherboard would have been too awkward to access inside the box. I found one at http://www.welovemacs.com/usb-key-bt.html for a reasonable price. I ordered one but the company NEVER shipped it after weeks of waiting. I gave up waiting. I then noticed that the Matias Tactile Pro keyboard had a start up bottom and great reviews about the feel, but just missed out on the demo model and refused to pay $175CDN for a new one. Lucky for me, Logitec announced at the MacWorld 2006 SF a new wireless keyboard/mouse combo (model S530 - $99) that APPEARS to have a start button from the pictures. It's not scheduled to arrive until mid February (Feb 1/06 release date), so I've been using an old green iMac G3 keyboard (has a start button) and standard MS optical mouse for the time being.
ATA port and Optical Drive: couldn't find a cable or figure out the ATA port used on board for the optical burner. Diagrams on the apple site show a cage around the optical drive that has a hard soldered plug, not the standard ATA cable/plug. Thought it was a laptop style drive, I'll work on finding a compatible cable in the future cause it would be good to add 1-2 more ATA drives at the full ATA/133 speeds instead of using Firewire. A simple firewire 5.25" enclosure is what I use now for the DVD burner. The LG4163 16x DVD-RW dual layer burner is disk bootable, but not iLife compatible. It works fine once I added the PatchBurn 4 utility. I did notice that Apple's DVD player does not support external DVD drives for movie playback. Again, off to Google to find an answer and it was found at this site with their patch.
Given that the ports for the mother board would be INSIDE the computer, I needed to find ways to access them. Video: There is an onboard port which most likely is a DVI video out. I will play with this later as it was easier to buy the Apple mini-VGA adaptor cable and run the video cable out the side. My 17" LCD doesn't have a DVI capability so when I do get a DVI compatible monitor, I probably will try to attach it then to the onboard video port and possibly dual desktop/spanning.
USB and Firewire: There are three USB 2.0 and 2 firewire 400 ports. From what I can gather, the USB are independent buses and the firewire is a combined bus. USB port 1: Plextor ConvertX PVR USB port 2: to a USB hub on the floor(printer/scanner, keyboard, wireless mouse, Digital Camera dock) USB port 3: to a combo USB 2.0 & Firewire hub that's on the desk - USB/Firewire ports are unused for now (but plan to use it for a DV camera, USB memory keys, iPod dock) Firewire 1: to a mini Firewire hub -> to the external DVD burner, external LaCie HD and to an iSight Camera Firewire 2: to the combo USB 2.0/Firewire hub that's on the desk (ie. for an iPod Dock or digital camera) Ethernet / Phone: Just ran them out of the side of the case using the above mentioned retractable cables     Sorry for the poor photos, some pictures are taken with a camera phone . I'll have better photography shortly.
The rest of the essential stuff I had spare parts or were easy pick ups at a local computer store
Future Additions
Final Words Basically everything works. There is no speed difference between a G5 1.8GHz iMac and my Franken Mac G5/1.8. Xbench scores are about 66-70 compared to a DP G5 2.0GHz. I wanted a G5 for my iLife apps as I found the Mac mini start to struggle a bit. So for a decent price, I have myself a fully functional G5 Mac with some uniqueness, a bit of flexibility in upgrades (hard drive, burner, monitor). Not a lot of savings for sure, but this thing FLIES compared to the Mac mini it replaced and it was a lot of fun to build.
questions can be sent to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it last update Jan 30, 2006
Originally posted on http://www.gsdye.com/FrankenMac/ Posted on MacMod with Dixon's permission
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