Project Silvertooth

[iMac600]

Some of you may recall the Power Mac G4 Quicksilver I picked up for the fantastic price of free not that long ago. It was destroyed by a student who fiddled with the voltage regulator, connecting a 110v power supply to a 240v line which vaporised the power supply and sent a deadly surge to the logic board.

Not even that will keep this Quicksilver down though. Presenting Project Silvertooth.

This is a true cut and assemble of three G4 systems of various series, the Sawtooth, the Gigabit Ethernet and the Quicksilver. The aim of the project is to assemble a machine that will run using a standard ATX power supply with minimal modification, offer comparable speed to a factory Quicksilver (if not exceeding it) while creating an all round funky machine.

ALREADY HAVE
- AOpen 400w ATX PSU

- Quicksilver 733 CPU Module

- 1GB SDRAM (PC133)

- nVidia GeForce2 MX 32mb

- LG SuperMulti Recorder

- 160GB HDD

- Quicksilver Case

- Sawtooth Rear Panel

- 12v CPU Booster Cable

- 4-Port Firewire Card + 1 Internal

- Bluetooth Connectivity

- Gigabit Ethernet Logic Board

- Mac OS X Leopard 10.5

- LeopardAssist 2.0 (for booting 10.5 on it)

- Imagine BootX (for creating a custom boot screen)

NEED

- PSU Extension Cable

- DIP Switch (Highly RECOMMENDED)

EXTRAS

- WiFi Card

- USB 2.0 Card

The Gigabit Ethernet logic board cost me $63 from Apple-Bits in Melbourne. Everything else on the list has been free or donated to the cause. I expect to spend no more than $100 on the project to get it running at full operating capacity. To clarify the need for some of these extra parts...

DIP Switch. Soldered into place on the logic board, this will allow changing of the frontside bus speed either up or down depending on switch configuration. I hope to achieve 133mhz or close to that amount, hence the need for all PC133 RAM.
12v CPU Booster Cable. Quicksilver CPU's used an extra 12v supply line to power the CPU module, similar to the Pentium 4 extra power connector. The addition of a booster cable connected to ground lug 4 provides the CPU with the 12v it needs to operate. Most CPU upgrade cards from PowerLogix and Sonnet also use this method.

PSU Extension Cable. This allows me to connect the ATX power supply to the Apple logic board, but also gives me a secure option to make the necessary output conversions for the power supply to work with the logic board. If the connections fail, then it's no big loss, these extension cables are quite cheap.

A Mac OS X Leopard 10.5 install disc has also been kindly donated to the cause by the school's IT administrative department, so a thank you to them for supporting the project to see their old server back in action.

I've often been asked why I would undertake such a challenging, time consuming or, as some have suggested, stupid project. Aside from the fact it will contribute to my electronics certification semester grade, it's also in the typical spirit of the 68kMLA. The machine is newer than most of our vintage Macs here, but it's still a system that, despite being abused all its life, will live again and see active service very soon.

I shall aim to keep the thread up to date on the project, with photos, as it progresses.

Cheers

- Michael

 

[benjgvps]

CPU extension cable: http://www.dealextreme.com/details.dx/sku.5199

If you combine these two, you can get a 20 pin to 20 pin motherboard connector: http://www.dealextreme.com/details.dx/sku.9818 http://www.dealextreme.com/details.dx/sku.5184

 

[iMac600]

Cheers, i'll keep those in mind for tomorrow. I have to stop by my local computer store anyway so i'll see what they have in stock first. CPU extension cable won't work since the 4-pin connector is only present on Quicksilver boards, on the earlier boards it needs to be hard wired to one of the CPU -> Logic Board retaining screws.

 

[Bunsen]

I see that the Gigabit and Digital Audio power pinouts are exactly the same. I succeeded in booting my DA from an ATX PS with an extension cable made for P4 logic boards. It had sufficient extra pins for the job.

If you're bus clocking, a packet of self-adhesive RAM heatsinks to lob onto any suspiciously warm ICs might be a good investment.

 

[iMac600]

I see that the Gigabit and Digital Audio power pinouts are exactly the same. I succeeded in booting my DA from an ATX PS with an extension cable made for P4 logic boards. It had sufficient extra pins for the job.
If you're bus clocking, a packet of self-adhesive RAM heatsinks to lob onto any suspiciously warm ICs might be a good investment.

Indeed, although i'm not sure how the RAM will respond as it will be clocked up to a theoretical maximum of 133mhz, and the RAM itself is already 133mhz. Better to be safe than sorry though, so i'll keep RAM heatsinks in mind when I next head in to the supplier.

Also, cheers for the link to the power supply pinouts. I forgot the link a while back and had been looking for it ever since.

Anyway, quick update. The board has been paid in full to the supplier and should be shipped down next week. I've also picked up a Belkin 3 Port Hi-Speed USB 2.0 card, designed for Mac (as it says on the box) so this should give the system a kick in terms of connectivity.

USB 2.0 card set me back $40, a little more than I had expected but it comes with a lifetime warranty and is quite a good card overall. Plus the assurance it works with Apple PowerPC logic boards is a big plus.

 

[iMac600]

Sat. 23rd August 2008 (5:25PM) - Quicksilver Roars into Life

What?

That's right. After spending a good $65 on a Gigabit Ethernet logic board, i've just gone and repaired my broken Quicksilver board in a last minute turn around. Using an extra 12v supply line plus a few alterations to an ATX I have around here, the Quicksilver has successfully booted up to a disk prompt, countering the belief by the IT administration and myself that the logic board was roasted.

So what does this mean for Silvertooth?

There will be two systems built. The Gigabit Ethernet board will occupy the chassis of my now dead Sawtooth along with a 400mhz CPU module and 384MB of RAM, at least until I can bump up it's specs.

I'll do more soldering tonight and hopefully get the Quicksilver up and running, leaving more time for the Gigabit Ethernet next week.

 

[Bunsen]

Congratulations!

a packet of self-adhesive RAM heatsinks to lob onto any suspiciously warm ICs

the RAM itself is already 133mhz.

I didn't mean specifically for the RAM. I thought there might be other ICs that might get a bit toasty, and would be more stable with a bit of cheap cooling.

By the way, the great advantage of doing the wiring mods on an extension cable is that if the PS ever fries, I can swap it out without having to do all that re-patching again.

 

[iMac600]

Congratulations!

a packet of self-adhesive RAM heatsinks to lob onto any suspiciously warm ICs

the RAM itself is already 133mhz.

I didn't mean specifically for the RAM. I thought there might be other ICs that might get a bit toasty, and would be more stable with a bit of cheap cooling.

Ah yes, of course, a mistake in my reading earlier. I agree some cooling for other IC's, particularly those handling the northbridge and southbridge which will be under increased strain on an overclocked system. I see what you mean.

I have a better PSU for the task as well, I will probably pick up an extension cable and do the necessary modifications to it when I visit the supplier next. Not too difficult to do.

I have a slight fear that I may need to use an extra power supply to provide the extra kick required to start it. I have another PSU here suitable for the task but intended to keep it as a last resort. It's becoming more and more clear i'll have to use it though.

 

[Bunsen]

Why?

Are you thinking of the +28V line? I had no problem substituting +5VSB (standby)

Otherwise, a G4 requires a -lot- less power than a P4

 

[iMac600]

http://www.outofspec.com/frankenmac/wire.shtml

Looking at the link you provided earlier, the two additional pins toward the top of the connector require at least 12v to start up- or so i've been told. If I could seriously connect it to just the 5v standby line and have it work, then this would be much easier. Like to hear more about your theory though, very interesting.

I don't intend for this power supply to be the final, I have a much better PSU lined up for the task. Tonight was the test run, the check to see if was actually possible to boot it up and I have to say, it's been a real success. Once I pick up the PSU extension cable, that's when the real fun will begin.

So it's now booted into Mac OS X Tiger... sort of. It's fairly unstable. The RAM I have in it at the moment isn't the most reliable stick i've ever seen, and the installation on the hard disk is quite old. Should be fine once the machine is cleaned up.

As promised, here are a few rough pics snapped with my iPhone during the process.

Soldered CPU Supply Wires

The Completed External Power Connector

My Cheap Soldering Station, Wiring up a fan

The Tower Open

Quicksilver Kicks into Life

Mac OS X Starting Up

I'll keep working on this further as more parts become available.

 

[MacJunky]

Bunsen, I was using 5VSB of my Antec NeoPower 650 Blue for my Digital Audio mobo but eventually after time it started loosing power under extreme load and right after power button press.(same thing happened with the first, second and third PC PSUs I was using with it) So, I went to the local PC shop to get an old AC->DC PC notebook adapter of acceptable specs, but I never ended up adding it. Thing is, while using a 400Mhz PII clocked to 533 during my DA's downtime I had a spur of the moment urge to replace it with a newer PC mobo to run OS X and windows and such.(I also did not fancy spending loads on an old GF6800GT when a muchmuch better PCI-e card was not much more)

That was late Feb and now here I am still using my Antec PSU and massively overclocked OS X running PC with absolutely no issues at all even with much higher power requirements.

I am about to put my DA back into service as a NAS device soon however. I need somewhere to store all my Mac stuff when I switch over my desktop to linux and windows use and have OS X on an Acer Aspire One that should be arriving next week.

So, I would always advise that anyone make sure to get something to handle the G4's rather high standby+FW+ADC or whatever requirements instead of relying on the PC PSU's 5VSB.

 

[iMac600]

That's where this next component comes in. Instead a connection of 5vSB, it will use a secondary internal 24v PSU from a PowerBook! The connections of the PowerBook PSU will be connected to the rear mains passthrough allowing the G4 to run from just one wall plug.

The only tradeoff is that external displays can no longer be plugged into the tower PSU, but the Quicksilver specification didn't allow such a setup anyway. (If you look at the rear plate of a QS, it only has one plug cutout on the PSU)

This should allow the G4 to run without any dramas and allow room for future expansion.

At the moment I have the machine shelved until the extra parts come in, once they do, I can begin work on the final revision.

 

[Bunsen]

Yep, after much headbanging on IRC with iMac600 and others, this was the conclusion we settled on. I have a box of 24V Powerbook supplies with dodgy cases I picked up at auction. I'm going to send him one, and install one on my DA.

Granted, it may not supply enough current to run an ADC display (4 amps!) but it should be enough to keep the logic board and a few powered Firewire devices happy.

 

[iMac600]

I remade some of the wiring tonight to a much neater design. Still needs to be tied together but it's otherwise working fine. Used a 20 to 24 pin extension cable this time as well.

For anyone else looking to attempt the project, i've put together a wiring diagram for the logic board connector.

Quicksilver ATX Wiring Diagram (Logic Board) (Updated- 31/08/08 )

It's still quick and dirty, and using 2 wall outlets, but the secondary supply in there at the moment is only a temporary fitting.

The success in starting it up was not without hiccups though. Initially the system had failed to boot because the ATX's "Power Good" line was connecting to a constant 3.3v line on the logic board, which for some reason shut off the machine on boot. Solution was to cut out the Power Good line and re-route it to run off another 3.3v line.

Then it wouldn't boot OS X, hanging during the boot process. This was another potentially major snag as we had suspected a defective L2 cache. Luckily the problem was just with the installation of OS X on the hard disk and, also after reconnecting the last 3.3v line, the system fired straight up into Mac OS X.

Just need to dive in and clean up the wiring now. I will still use the PowerBook supply, the system is already prepared for it as i've soldered in plugs rather than a direct wire-to-wire solder. When the PowerBook PSU gets here, pop out the old Hewlett Packard 19v, slide in the PowerBook PSU and plug it in. Simple.

From there it's really anyone's guess, I could pull the HD from this eMac and drop it into the Quicksilver I suppose. The speed difference over the eMac is noticeable, plus it has USB 2.0.

 

[ccmac]

Check out the following:

http://zots.ath.cx/atxg4/atxg4.html

http://www.atxg4.com

http://forums.macrumors.com/showthread.php?p=5245583

http://www.io.com/~trag/28v_vreg.pdf

 

[Bunsen]

That guy's diagrams are pointlessly confusing. The one on outofspec is much clearer.

But in the end it was someone in IRC who sent us the pinout from the Apple service manual who straightened us out. Thanks.

Yours looks nice though, iMac600

One thing though, that threw me at first: there's a convention that lines that cross but don't join should have a little "jump" in one of them to make it clear, like a little bow shaped bridge over the other line. As drawn, it looks like there's a whoooole lotta short circuiting going on.

Either that or route them outside so they don't cross any of the other lines.

 

[iMac600]

I still have the source file for the diagram (OmniGraffle Pro) so I'll make some minor changes later. May make up a wiring diagram for the mains power passthrough connector as well, for reference.

When I'm satisfied with the wiring, I'll install Leopard on it, mostly for fun but we'll see how it goes performance wise. See where this machine hits its limit.

 

[iMac600]

Installed Mac OS X Leopard. So far i'm pleased with it, it's not a bad operating system on this CPU and Graphics Card. Speed isn't sacrificed too much for the functionality... it's like Tiger is on a Yikes or Sawtooth- it's hardly an Intel Mac but hardly a slouch either.

LeopardAssist worked fine on the Quicksilver and allowed for a flawless install of OS X Leopard on the slower CPU. I'm pleased to hear this as it's taken me months of updating and programming to make LeopardAssist run on the majority of G4 systems.

Speaking of which, it may be a good time to test concepts for a Leopard Optimiser on older systems. I've been tempted to make Leopard run at its very peak on older systems for a long time when I wrote down the guidelines for "LeopardAssist + TurboCat" six months ago. Now I have the chance to test it first hand.

 

[Christopher]

So like you could make leopard run on a G3?