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EDENstation 5 project

So, let's say you've got this Sun SPARCstation 5, and you like the compact dimensions and classy design. But you don't really know very much about Solaris, and you certainly don't know enough about Linux to wrangle it onto a recalcitrant TurboSPARC. And let's say you do need a low-power, low noise PC. The answer: stuff in a VIA EPIA 5000 motherboard and turn it into an EDENstation 5.

VIA's Eden CPU (clocked at 533MHz on the EPIA 5000 motherboard) provides modest processing power by modern standards, but it's quite adequate for a small file server, web server or firewall. It consumes very little power and doesn't need a fan, only a passive heat sink. Combined with a fanless PSU and a compact flash card instead of a hard disk, it can be built into a completely silent PC.

Read on to see exactly how I did just that. You can click on any of the photos to see a larger version in a pop-up window.

No SPARCstations were harmed in the making of this computer

I can already hear the wails of the die-hard SPARCisti, appalled at the idea of butchering a perfectly good SPARCstation. Well to tell the truth I felt a certain pang of guilt about it myself. So I did my conversion without any cutting, drilling or other modification of any of the original components. It would take about 5 minutes to plug the SPARC parts back in and the machine would be restored to its former glory. Score 1 for Sun's impressively modular design.

So what about this SPARCstation 5 then?

The SS5 is based on Sun's "Aurora" chassis, one of the "pizza-box" SPARCstation designs. Some other SPARCstations used the "lunch-box" form factor, like the IPX that Mark Gill used for his EdenStation IPX project. The Aurora chassis was also used on the SPARCstations 4 and 20, as well as a number of server-oriented versions. The SS5 seems to be the most widely available though. I picked mine up for under £20 on eBay.

If you're buying a SPARCstation 5 for a conversion project it's worth noting that there were two versions of the Aurora chassis. Pre-1996 machines were fitted with a normal-sized 3.5" floppy drive, and a specially made 1" high CD-ROM. In the post-1996 version, Sun squeezed down the floppy drive bay to allow the fitting of a full-sized CD-ROM drive. The smaller floppy drive in the newer machines is of the same form factor as the widely available slim-line PC floppy drives.

Stripping the SPARCstation

Click to see a larger picture of the interior of the original machine

Undo two screws at the top of the back panel, and the interior of the original machine is revealed. One more captive screw (on the left of the picture above) needs to be undone to remove the PSU. The floppy, CD-ROM and SCSI hard drives all lift out without undoing any further fasteners. Four more screws release the speaker and the SCSI daughterboard, and finally two more screws free up the motherboard assembly. The motherboard, back panel and all the adapter cards then slide out as a single unit on plastic rails:

Click to see a larger picture of the SPARCstation 5 motherboard assembly

This motherboard is fitted with three cards: from left to right, two network cards and a graphics card. Server versions of the SPARCstation 5 were available with no graphics card fitted. The 170MHz TurboSPARC CPU is hidden under a small heatsink and fan, near the far left corner of the board as seen from this angle. Variants with 70, 85 and 110 MHz MicroSPARC CPUs were also available.

Now we're left with the stripped chassis:

Click to see a larger picture of the stripped SPARCstation chassis

Mounting the motherboard

The major part of the build was to fabricate an aluminium base plate and back panel, to replace the SPARC motherboard and back panel. The EPIA 5000 and a compact flash-to-IDE adapter would then be mounted on the base plate. So I picked up some aluminium sheet and angle sections, and got to work with the hacksaw, Dremel and rivet gun. Here's the finished metalwork:

Click to see a larger picture of the motherboard mounting tray

And here's the complete motherboard module with all the electronics in place:

Click to see a larger picture of the assembled motherboard module

There's the EPIA 5000 motherboard, a 1U PCI riser card, a PCI ADSL modem, and for storage a compact flash-to-IDE adapter with a 256MB CF card. The other small circuit board that you can see is to control the case LED - more on that later.

Power supply

Now for the power supply. I'm using a Morex 55W fanless power supply kit. For neatness I wanted to mount the power-brick inside the case. That does carry the risk of overheating problems; but the SPARCstation case is very well ventilated, and I haven't had any heat problems with the machine so far.

I fabricated a tray to hold the power supply components that would slot in in place of the Sun PSU. Again this was sheet aluminium, with a little bit of galvanised steel mesh on the side to stop too much RFI escaping out of the large holes in the side of the SPARCstation case. On the back panel of the PSU tray I installed an IEC mains inlet socket, a hard power switch, and a push-button switch to connect to the motherboard's power switch header.

Click to see a larger picture of the power supply mounting tray

Step 2 was to attack the Morex power kit with a pair of side-cutters to hack off the bits of cable I didn't need. The bits I threw away are on the left:

Click to see a larger picture of the mains power adapter

On the right is the bit that's actually used. The AC-in "cloverleaf" plug is wired to push-on connectors that will go onto the terminals of the hard power switch, and the DC output from the power brick is soldered directly to the plug that connects to the DC converter board. Here's the completed power supply unit:

Click to see a larger picture of the assembled PSU unit

Final assembly

Now for some assembly! The motherboard module slides in on the original plastic rails, and the PSU slots in. They're secured with a few screws. I dropped the original floppy drive back in - just to fill the hole really, I'm not using it as the EPIA 5000 has no floppy interface. On top of that I fitted an old 12X-speed IDE CD-ROM drive. It's not actually connected, as I'm not using it at the moment. It only draws 0.8A on the 12V rail so I probably could use it if I needed it, even with the weedy 55W power supply.

Click to see a larger picture of the interior of the fully assembled machine

It's interesting to compare the fully assembled machine with the original SPARCstation internals. I've used most of the space in there, and I only fitted one expansion card whereas Sun managed to squeeze in 3! Sun are no slouches when it comes to small form factor design…

A couple of additional details of the case assembly: first a look at the left side of the front of the case, where the speaker is normally fitted.

Click to see a larger picture of the reset switch

The EPIA motherboard has an on-board buzzer so the case speaker isn't needed. I covered the hole with a piece of aluminium and used that as a mounting for a small reset button, hidden behind the speaker grille. If you wanted to fit additional lights to a SPARCstation 5 case, this would be a handy place to do that as well.

At the right-hand side the SPARCstation has its power LED. I replaced the standard green LED with a slightly funkier blue one:

Click to see a larger picture of the power/hard disk LED set-up

The small circuit board in the picture above lights the single case LED dimly to indicate power-on, and flashes it brighter to show disk activity. The IC on the circuit board contains two optocouplers, into which the LED signals from the motherboard are fed to perform the switching. You could probably do the same thing slightly cheaper with transistors, but using the optocoupler is simpler and has the advantage of isolating the expensive motherboard from my dodgy electronics.

Finally a couple of views of the completed machine:

Click to see a larger picture of the completed machine


http://www.obsolyte.com - SPARCstation info

http://www.mini-itx.com - loads of other VIA EPIA-based projects and general mini-ITX-form-factor news and info

Places to buy VIA EPIA motherboards and accessories (in the UK):