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The beige G3 logic board that wouldn't die (Beige G3 µATX build)


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Hello,

 

This is a little bit of a blog post, if this is more suited to "The Lounge", please let me know.

This is the story of my longest running Macintosh (nicknamed Pulse), which is still running 24/7 after 17 years.

 

Intro

A while ago, circa 2002-2003, an apple reseller gave me a dead G3/233 Desktop. When I said "dead", I mean it wouldn't boot and half of it was missing:

- Top of the case was missing

- The whisper personality card shield was missing

- Case was bent, was probably dropped 

- No RAM

- No HDD, No Optical Drive

 

Repair procedure

As I needed a new file server (my Performa 6400 was dying), I though it would be a good idea to repair it. The Mac was not starting, but after trying with RAM borrowed from a Pentium III and an ATX PSU, I heard the chime but the display cas scrambled.

The VRAM extension card was defective, I managed to reflow it in a kitchen oven, and put it later on my MT/300 G3 as VRAM isn't really needed on a server.

There you go, it was sort of alive again. 

 

I needed some sort of storage backend and decided to go with a combo of SCSI and hardware SATA RAID (SATA for OS + Files, Using old SCSI drives as backup). I was so impressed with the performance that I upgraded the CPU with a Sonnet Encore G3 500/1M (https://everymac.com/upgrade_cards/sonnettech/encore_g3/encore_g3_500.html). System bus was overclocked at 83 MHz (83 * 6 = 500 MHz) 

 

It ran for a few years on a bad ATX case stacked on a top of rack, thinking it would die a few months after. 

 

New Case / Rebuild

More than 10 years later (2016), being impressed that this Mac was still running, I decided to put it back together in a more clean build. The chosen case was a white cube : Corsair Carbide Air 240.

 

Corsair%20Carbide%20Air%20240.jpg

 

The motherboard was almost fitting without too much issues

 

Motherboard%20fit.jpeg

 

I had to cut a little bit of the backpannel to fit the SCSI Connector :

 

SCSI%20Connector.jpeg

 

It got a new PSU for this occasion.

 

Current configuration

The current configuration is as follow

- MB Apple PowerMac Gossamer Logic board

- CPU : Sonnet Encore G3 500/1M

- Bus : 83 Mhz

- RAM : 640 MB

- OS : Mac OS 8.1 (Bootstrap + Maintenance) + Linux Debian 8 (Custom Kernel)

- SCSI : Onboard SCSI (for external disks) + Adaptec PowerDomain 2940UW (flashed from a PC Card)

- SATA : Bootable Silicon Image 3112 + Hardware RAID Module (stolen from an external RAID Array)

- High end ATX PSU (don't remember which one, probably Enermax or Corsair branded)

 

An inside view:

The blue led board is the hardware SATA RAID Controller

- The CPU coller comes from an Athlon XP system, with the fan removed

 

Inside.jpeg

 

Usage

Today it's still used and has no time to sleep : It's used as a file server (Netatalk), DLNA Server (Audio), DNS cache, DHCP server, SSH Gateway and Syslog server.

It gained an Apple Logo on a front, courtesy of a broken Quadra 800 Front panel

 

Front%20logo.jpeg

 

Here is a little Linux output :

 demik@pulse  ~  cat /proc/cpuinfo 
processor	: 0
cpu		: 740/750
temperature 	: 27-29 C (uncalibrated)
clock		: 501.150000MHz
revision	: 131.2 (pvr 0008 8302)
bogomips	: 33.41
timebase	: 16707866
platform	: PowerMac
model		: Power Macintosh
machine		: Power Macintosh
motherboard	: AAPL,Gossamer MacRISC
detected as	: 48 (PowerMac G3 (Gossamer))
pmac flags	: 00000000
L2 cache	: 1024K unified pipelined-syncro-burst
pmac-generation	: OldWorld
Memory		: 640 MB

 

Conclusion

If I can think of a series that can continue to run on standard "PC" parts, this is the Gossamer Logic Board. Everything can be found easily even today. My PowerMac G5s are dying left and right, and I've yet to see a Gossamer logic board to fail. Sure, there is the occasional VRM cap to replace, and I need to replace the fans soon. (bearings are shot)

 

The PPC750 is also a very simple and stable CPU. One of the best designed CPU of it's erra. It has few bugs online modern x86 counterparts. Thats also part of why it's running on Mars since almost 10 years (https://en.wikipedia.org/wiki/Curiosity_(rover))

 

Will keep this one up for science until the motherboard dies :) 

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This is tremendously cool, possibly the best-loved G3 ever when it comes to your dedication in prolonging its life. I love seeing a machine that's lived a long and useful life.  

 

I'd be wary of survivorship bias though: I know from personal experience that the Gossamer boards can develop flaky solder connections on the expansion slots over time. That said, I've seen it suggested a few times that running a computer 24/7 tends to be better for its longevity than turning it off at the end of each day and allowing it to cool down. My Quicksilver G4 ran flawlessly 24/7 for over a decade yet immediately became an unreliable heap once I put it on a daily power plan. The solder on the RAM slots had cracked and wreaked havoc. 
 

The G3 is such a glorious halfway house between technological eras. The step up from the 604 was immense yet the G4 came and stomped on it so soon after its birth. I'd love to see a homebrew logic board for G3s emerge some day - that would be such a fun low-power tinkering machine. 

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17 hours ago, PowerMac_G4 said:

This is tremendously cool, possibly the best-loved G3 ever when it comes to your dedication in prolonging its life. I love seeing a machine that's lived a long and useful life.  

 

I'd be wary of survivorship bias though: I know from personal experience that the Gossamer boards can develop flaky solder connections on the expansion slots over time. That said, I've seen it suggested a few times that running a computer 24/7 tends to be better for its longevity than turning it off at the end of each day and allowing it to cool down. My Quicksilver G4 ran flawlessly 24/7 for over a decade yet immediately became an unreliable heap once I put it on a daily power plan. The solder on the RAM slots had cracked and wreaked havoc. 
 

The G3 is such a glorious halfway house between technological eras. The step up from the 604 was immense yet the G4 came and stomped on it so soon after its birth. I'd love to see a homebrew logic board for G3s emerge some day - that would be such a fun low-power tinkering machine. 

 

Thanks for the input ! I only saw the flaky connections on G5 and some late G4s, will keep an eye on it. 

 

You are spot on with the 24/7 longevity. Maybe that's why this one is still running. Another important thing is that there is very few heat produced by a gossamer logic board. Power Wall consumption is under 50W on my system.

Heat play a major role on solder connections.

 

Unfortunately this is less true on today computers, because they heat a lot more (excluding Apple M1) and with dynamic power features it's like you are putting on a power plan multiples times a day...

 

As for the home-brew logic board, it was done by the Amiga Community under the Pegasos name (https://en.wikipedia.org/wiki/Pegasos

The G3 processor doesn't look like to be produced anymore. The G4 is (MPC7448 at least), but prices are a bit on the expensive side (up to $500 a single unit). Then there is the soldering problem, soldering BGA components is kinda hard (well there is the oven trick, but soldering $500 components in your kitchen oven isn't something that many will do).

 

That would be cool, but technically difficult for a home-brew board.

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This is really nice.  Especially the Apple logo.  Well done.

 

Will third the fact that power cycling is enormously harder on machines than just running them all the time.  I've always assumed this is thermal stress but have never looked into it deeply.

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On 2/10/2021 at 7:28 AM, cheesestraws said:

This is really nice.  Especially the Apple logo.  Well done.

 

Thanks. I'm bad at cursing thing straight though...

 

On 2/10/2021 at 7:29 AM, joshc said:

This is really interesting. I have often wondered about how to best adapt an ATX case to some of these Mac logicboards. I really like your implementation, thanks for sharing it!

 

Thanks ! From my experience G3 and early G4 Motherboards are easy to adapt, though you will need to do new fixing holes.

On 2/10/2021 at 8:00 AM, PowerMac_G4 said:

 

Those crazy Amiga fans! Thanks for the heads up on that - I'll get on the hunt. It'll probably take half a decade but I'm sure one will show up on ebay eventually...

 

Speaking of which, if you need a home-brew G3/G4, maybe you can start with a G3/G4 motherboard ? They are plenty of Sawtooth and similar motherboards for like $10 on eBay and QS 733 MHz CPUs are around the same price. They play with ATX PSU just fine if you do an harness adapter.

 

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This is really cool, although I'll admit I was a little sad when I got to the part where it's doing AppleShare services using Netatalk instead of AppleShare IP or even Mac OS X/Server 10.2.

 

What's the RAID module do? Are you presenting a larger volume to the SIL3112 or does it mostly just offer SATA splitting?

 

I have thought about doing something similar to this, although using a dA/QS motherboard and several SIL3112s, mostly to keep the QS02 I'm running AppleShare on going a bit longer.

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This is very cool! I actually just order a bench frame for my G3 Tower MOBO and plan on something similar. Right now it runs an IDE to Compact flash for a drive. Can you elaborate any on your SATA setup for your system? I would love to run SATA drives on this computer.

 

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On 2/16/2021 at 11:52 PM, Kaa said:

This is very cool! I actually just order a bench frame for my G3 Tower MOBO and plan on something similar. Right now it runs an IDE to Compact flash for a drive. Can you elaborate any on your SATA setup for your system? I would love to run SATA drives on this computer.

 

 

There is two parts of this setup, the SATA card and the RAID module which is explained below

 

For running SATA on old Macs, you can go three ways :

Host IDE to SATA adapter

They plug directly into the IDE port. Compatibility : poor, do not work most of the time. They look like this :

 

sata%20to%20ide%20host.jpg

 

 

Do not recommend.

 

Disk IDE to SATA adapter

This is another converter, but it convert a SATA disk to an IDE disk. Those works better, although it's not guaranteed. (RevA Gossamer boards are not fully IDE compliant) . They look like this :

 

sata%20to%20ide%20disk.jpg

Available online at around $10. So for this one it's worth a shot.

 

SIL3112 SATA Controller

This is the best way, but also not so easy

This controller is not AHCI compliant and was used in early SATA days in both Macs and PCs. The good thing about it is, there is a firmware avaible for Mac. So you will need to find a PC SIL3112 SATA based card and flash it to work on your mac. After the flash, the card will be bootable on G3+ macs. 

 

Photo for reference :

 

Sil3112%20PCI.jpg

 

There is a flashing tutorial on macros here : https://forums.macrumors.com/threads/guide-to-flashing-pc-sil3112-sata-cards-for-mac.1690231/

 

I can boot Mac OS 8 just fine on it ! 

 

On 2/15/2021 at 10:45 PM, Cory5412 said:

This is really cool, although I'll admit I was a little sad when I got to the part where it's doing AppleShare services using Netatalk instead of AppleShare IP or even Mac OS X/Server 10.2.

 

What's the RAID module do? Are you presenting a larger volume to the SIL3112 or does it mostly just offer SATA splitting?

 

I have thought about doing something similar to this, although using a dA/QS motherboard and several SIL3112s, mostly to keep the QS02 I'm running AppleShare on going a bit longer.

 

Yeah, the Linux part I can explain it. Back in those days, I was using a Mac OS 9 and Linux workstation setup. I switched to OS X around 10.4.8 when everything was running fine on it. Then this build was used as a WAN router for some time, OS X isn't the best as this, and I wanted security updates.

 

As for the RAID Module. It's a standalone RAID controller that is used on some servers backplanes or external SATA enclosures. Mine only does RAID0/RAID1 but some more expensive can do RAID5.


What I basically done was to steal this part from an eSATA RAID Enclosure and integrated it into the Corsair case. The OS only sees a virtual SATA disk. This gives you better performance because the RAID part iOS handled at the RAID module chip and not at the OS level. Also you get hot plug as a bonus.

 

My current setup looks like this :

 

[ PCI SLOT ] <-> [ SIL3112 Controller Port A ] <-> [ RAID Module (RAID1) ] <-+-> [ SATA Disk 1 ]
                                                                             \-> [ SATA Disk 2 ]

 

You can also use the external SATA enclosure directly with a SATA to eSATA PCI Bracket.

 

Hope that helps.

 

Regards

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On 2/21/2021 at 7:23 AM, demik said:

After the flash, the card will be bootable on G3+ macs. 

 

Unless this is a function of like the bigger/smaller ROM sizes for this card, it should also boot 7.5/7.6 on pre-G3 PCI PowerMacs, although 7.6.1 is needed for the biggest volume sizes. With that in mind these cards are basically the best extant option for any PCI Macs, but the availability of cards is always a thing.

 

On 2/21/2021 at 7:23 AM, demik said:

Then this build was used as a WAN router for some time, OS X isn't the best as this, and I wanted security updates.

 

That is wild -- fair, but wild. I can't imagine wanting to use a G3 for that, but I'm sure it would've been fine at speeds then. (Especially since I have full confidence linux could use more of the platform's speed and saturate both onboard 10mbit and PCI 10/100 cards better than OS 9 can.)

 

On 2/21/2021 at 7:23 AM, demik said:

What I basically done was to steal this part from an eSATA RAID Enclosure and integrated it into the Corsair case. The OS only sees a virtual SATA disk. This gives you better performance because the RAID part iOS handled at the RAID module chip and not at the OS level. Also you get hot plug as a bonus.

 

Also wild. I'll admit I didn't realize this kind of thing existed, although, I suppose really should have. That would be a very convenient way to get mirroring, my original plan with OS 9 was to get that just using somewhat frequent backups and my current best idea is to do it in OSX software, although that'd be by USB and there's Lots of Concerns, potentially, there, so, "we'll see".

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On 2/21/2021 at 3:23 PM, demik said:

Host IDE to SATA adapter

They plug directly into the IDE port. Compatibility : poor, do not work most of the time. They look like this :

 

It is good that I read this after trying because I just might not have bothered to. I got one of these for a Mirrored Drive G4 and it works just fine. I put it into the ATA-66 Slot, connected a 120 GB SSD and was able to format and use it without problem. Cloning the system disk and booting from the SSD was also no issue -  MacOS 9.2.2 as well as 10.4.8

 

So at least for late G4s this seems a good and cheap option (just north of 10 Euros). G3s and earlier G4s with their somewhat different/incomplete IDE implementation may be a different story. I have none to test that.

 

Now only have to get an IDE extension cable to be able to put that thing into the ATA-100 port. There is no room for the adapter in its location on the board, but extensions are easily available.

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On 2/22/2021 at 6:56 AM, Cory5412 said:

Unless this is a function of like the bigger/smaller ROM sizes for this card, it should also boot 7.5/7.6 on pre-G3 PCI PowerMacs, although 7.6.1 is needed for the biggest volume sizes. With that in mind these cards are basically the best extant option for any PCI Macs, but the availability of cards is always a thing.

 

The full SeriTek ROM will do Classic Mac OS, so 9.2.2 and lower. That does require a bigger ROM to be installed, which also has to be a specific EEPROM as the SeriTek firmware does check the manufacturer of the chip against a whitelist, probably as some rudimentary form of copy protection. The cutdown, smaller Wiebetech ROM is OS X only and will not do Mac OS Classic, full stop.

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Thanks for the tips! I've tried the IDE to SATA adapter (middle one) with no luck. When I get a bit of time I may mess around with the SIL3112 card and flashing it. Was hoping for a bit easier of a solution. I did order an IDE to SD adapter card ($12) off Amazon so that will likely be my first fiddling with a drive for this build. The IDE to CF works great and is super easy, so I'm hoping the SD version will as well. I can probavly live witout SATA for this G3 if the SD version works. It's just nice to have some modern storage options.

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