Ooooooh this is my jam!
With luck you should be able to obtain some suitable screws if you can obtain the thread specifics... I can pull a screw out of one of mine and see if i can do some research if it helps. hopefully they arent a near impossibly to get proprietry thread like some grub screws and machine screws used in other electronic equipment (such as Jaycar amplifiers).
But yes, I have a couple of these... One of them started life as a 300 Rev.1 like yours and I built it about 13 years ago for video-editing. I was one of the few Rev.1 owners to not have the IDE corruption issues with non-OEM hard drives, however when I became privvy to the inherent shortcomings of the Rev.1 board (and also became tiresome of the hobbled 300Mhz chip with it's small cache), I purchased a secondhand Rev.2 logic board complete with 450mhz CPU and heatsink, and the slightly faster video card, and experimented with overclocking to 500mhz, which worked fine with an extra fan added to the CPU heatsink. I had picked up another G3 with a bad logic board very early in the piece as well i purchased cheap, and succeeded in overclocking it to 450mhz from 400mhz with great results.
I also have a second one that is flashed for a sonnet G4 processor, which is running my stock 350mhz Yikes G4 chip, and my Yikes is running the 500mhz sonnet encore chip. Unfortunately you cant make proper use of a G4 chip on a G3 board without the Sonnet firmware flash, and possibly won't recognise it at at all... I will try it out on my unflashed G3 to confirm. As stated above, the G3 Yosemite and G4 Yikes boards are almost identical, with the Yikes basically being little more than a third revision G3 board. It has firmware which supports a G4 CPU natively (for obvious reason) and also has ADB componentry deleted from the board. If you can get a Yikes logic board, you will be abe to run an Encore 500mhz upgrade ZIF natively, plug and play. Also as mentioned, the cases are identical in construction except for the removable backplate for the port panel. So if you are able to find a dead Yikes G4 or empty Yikes case, then you could either swap the working internals into that case, or rob parts to fix your case. The Sawtooth cases are also very similar so all external plastics should interchange, however internal bosses, pressings and mounts may differ. The DA and onwards start to increasingly differ... that said the feet may still interchange with luck.
Anyway, that all aside, some other info that is possibly of some use to you...
Max RAM ceiling is 1Gb with 4x256Mb 168-PIN PC100 SDRAM modules... 133 is also acceptable.
Maximum CPU speed using onboard multiplier jumpers is 500mhz. There was at one point a 900mhz upgrade released however this from memory slowed the system bus to 66mhz. CPU and bus clock are controlled by a jumper block on the logic board with a WARRANTY VOID IF REMOVED sticker. This allows for a lot of playing, but please do not touch this without being fully aware of what you are doing!!!
You can put up to two HDD's of up to 130MB capacity each onto the primary 100mhz IDE bus, and you will note that there is room for at least 3 or 4 drives however. This is because the G3 was available in server form or or optionally with a SCSI adapter on the PCI bus to allow support for many and large drives. This in itself makes me think Aplle knew about the corruption issues, but I digress. Anyway, you may notice an extra IDE plug for a slave drive on the secondary bus below the CD drive. this was intended expressly for the optional ZIP drive. Whilst some people find it tempting to place a Hard drive in this space, this is not advisable for a number of reasons. The first, and this is one i learned the hard way building a machine for my high school, is heat... A hard disc mounted in that ZIP bay lasted all of a year in that machine (this is the machine running the yikes processsor and a sonnet reflash, before it failed due to overheating. Secondly, the secondary IDE bus is only a 66mhz bus, so therefore throughput speeds are far slower when accesssing any hard drive attached to it. And lastly, there is the Master/Slave issue. As a G3 or G4 of this era is not able to boot from the secondary slave, if you have the CD-ROM as the slave drive, it will be an unbootable drive in the event that you need to boot from it. the only way around it will be to change the config to slave. Now I hear you ask "Why not just run it as master then?"... Well, the problem is, if there is no volume in the CD-ROM drive at boot time, then the computer will skip looking for a slave drive on the secondary bus, so your hard drive will be unmountable, unless you restart the machine with a CD in the drawer. It's an odd little quirk, but one worthy of note nonetheless. In any case, you really dont want to have to be keeping a CD in the tray just to have your G3 detect a hard drive.
Also something worth mentioning, is that the B+W G3 and the Yikes G4 were the first Mac's to have built in firewire. Now, the firewire ports and controller themselves have been known to get flakey with repeated hotplugging and general use. However the point that actually brought me to mention firewire was pointing out that unlike the Pismo Powerbook, slotload iMac, and Sawtooth G4 and all their succesors, the Yosemite/Yikes towers do NOT support firewire booting, nor do they support "target disk mode", which is the function by which you may effectively boot the machine as an external firewire device to another computer, allowing you to access it's volumes as if they were external removable drives.
One last thing that is worth mentioning, is that these machines are notorious for doing all sorts of things after major or even minor changes, or even after sitting unpowered for ages.If the machine becomes unbootable, don't be scared to hit the cuda switch on the logic board, hold the interupt button in on startup, zap the pram half a dozen times or whatever, in any sequence you please until it works again, as usually it will. When I got my G3.5 given too me 3rd hand (the one i built in high school), it was totally unresponsive and presumed dead. I reassembled it and after a lot of cursing and various resets and things, the stubborn thing came to life and has worked since.
I've also had to do a cuda reset on my G3 and Yikes every time ive changed CPU's or CPU jumper configurations, or they simply wont boot.
Anyway, enjoy!
