Slot Loading iMac G3 W/ 550Mhz G4 Processor Upgrade & 10.5 Leopard (First Look)

[SabithaSuki]

So I will paraphrase from the YouTube description about the situation

[youtube]UmP7d5m_CLw[/youtube]

I didn't want to keep this find to myself. I got this from a consignment seller, but I don't actually know it's true origin beyond a hell of a good modder.

The board pictured shows the G4 chip on the logic board as well as the system profiler on the main CRT.

It boots, and has been on for 2 1/2 hours during the initial Carbon Copy Cloner backup, and it has both speakers working (though replaced due to foam rot) as well as the headphone jack working, but the Airport card isn't showing anything, though that may be PRAM battery related.

I plan on making an extensive view of the computer once I get a replacement inner bezel that I cracked trying to install and set up everything post cleaning

If ANYONE happens to know where I can get the inner bezel for a slot loading iMac G3, let me know.

Who knows? I can give a shout out to the next person who helps complete this monumental piece of G4 History.

The main reason I'm posting here for is to show that it can, and has been done, even if the documentation on the internet has been sparse. I scooped this up on eBay and am determined to give it a good home (Even got a rare logo-less faceplate typically used on television props) with a fellow hardware hobbyist in mind.

[n8blz]

Hello fellow iMac fren,

Cool Mod. Wonder how the heck that guy did that!

We are in the process of getting a 3D scan and possibly a mold made for the inner bezels. Wondering if we should crowd source this project or keep it to ourselves. If we get enough people interested we might just release the STL. Total estimated cost for the mold option will be around $2500-3500CAD. This would allow us to mass produce these inner bezels at factory spec + plastic enhancements to prevent said cracking. The 3D printed STL might still work, close as we can get it, but you would need a printer large enough for it and have direct drive capabilities to use stronger plastics.

[refinery]

FastMac and I believe Daystar as well did CPU swaps on these systems. They were never particularly popular because of the otherwise limited nature of upgrades you could do to these machines

[dosdude1]

The G4 upgrade is actually pretty easy to do on most systems, I've done many (including slot-loading iMac G3s). Any G3 machine that uses an IBM PPC750L or Motorola XPC/MPC750 CPU can be upgraded to a 7400 or 7410 G4 CPU, as they are pin compatible. The only nuances you have to look out for are CPU VCORE voltage; this needs to be set accordingly before installing your G4 CPU. It is done by changing resistor strap configs, or changing resistor values, depending on the machine. The other thing you need to be aware of is L2 cache I/O voltage (L2OVdd). The 7400 supports 3.3V L2OVdd, however the 7410 only supports 2.5V L2OVdd, and cannot be used on boards that use a 3.3V L2OVdd. Lastly, if you really want to get fancy, you can upgrade the L2 cache. I've upgraded some machines from 512K to 1MB. The following machines can be G4-swapped:

• PowerBook G3 Kanga (maybe, but untested), Wallstreet, PDQ, and Lombard - 7400 only
• PowerBook G3 Pismo - 7410 or 7400
• iBook G3 Clamshell (non-Firewire) - 7410 or 7400
• Some slot-loading iMac G3s (that use PPC750L) - 7410 or 7400
• All tray-loading iMac G3s - 7400 only
• All PowerMac G3s (Beige, B&W) - 7400 only

If you have a machine that can work with a 7410, it is highly recommended. Not only do they run cooler than the 7400, allowing you to increase clock speed a little bit more, but they are much easier to find for sale. I do intend to see if I can modify the L2OVdd voltage on some boards/CPU cards, in order to install a 7410 on all these systems. However, it looks like doing so may be difficult, as these tend to have L2OVdd tied directly to the 3.3V OVdd rail.

I've attached a couple photos below of one of my tray-loading iMac G3 upgrades; with a new 7400 CPU installed, upgraded 1MB of L2 cache, and running Leopard.

[refinery]

@dosdude1 is that a service you offer for people? I have a couple I have been wanting to upgrade but my skill level is nowhere near the ability to do BGA rework yet. I can source the CPUs easily enough.

[dosdude1]

@dosdude1 is that a service you offer for people? I have a couple I have been wanting to upgrade but my skill level is nowhere near the ability to do BGA rework yet. I can source the CPUs easily enough.

Yep, it sure is, I do these upgrades for people quite often. Just send me a message and we can arrange.

[AssortedSordid]

I too would very much like to take advantage of this service for my Pismo, I’ll PM you soon as I’m at work right now if that’s alright