There is no way to edit my original posts so this one will have to do.
Something I've noticed over time is how finicky 9600 machines can be when there is a PRAM battery issue. Sometimes you'll have trouble booting the machine from the keyboard's power button if there is no PRAM battery installed, or if it's weak. I've heard that when you get down to around 3V, it's time to replace it. The batteries should read 3.6V when brand new. One of my 9600s had this exact problem until I changed it.
On top of that, I find that sometimes I have weird trouble with bootup times and things going slow when a PRAM battery isn't installed. It'll take forever to boot sometimes when it's searching for a hard drive. I even had trouble installing some software on an external drive because the PRAM battery wasn't installed! It just stalls or freezes.
All of the above is especially true for the older Tsunami architecture machines. For some reason the 200 and 233 machines suffer from more weird issues when there is a low, dead, or missing PRAM battery. Just random issues that make no sense. This is another reason to try and find a 300 or 350 machine. Whenever you have some issue that you just can't pin down, as weird as it may sound, the PRAM battery can make things go haywire, so check the PRAM battery and see if it clears up the issue even if you think the problem you're having is completely unrelated to the PRAM battery. They're only like $4 brand new. 1/2 AA 3.6V is what you want.
I've also found that you need to make sure you've got good RAM, and that it is seated correctly. Sometimes I'll get a broken glass sound (indicates RAM issue) but all it takes is pushing the RAM down into the slot better. I'm not sure if this has any connection to it, but I noticed this more so on my 200 machine than my Kansas ones.
One more issue is that on my 200 machine, I think there may be an issue with RAM slot order. All of my Kansas machines work fine with the RAM installed as I posted in the original guide: the '6' slots first, working back. However I've found the Tsunami one wanted me to install the first stick vice versa: slots '1' and counting up. Perhaps this was just a fluke and I wasn't seating the RAM correctly, but changing slot order on an older Tsunami machine is another troubleshooting method you can try for a non-booting machine. If you start up and don't hear the chime, fool with the RAM by either switching slot order or reseating it well and see if that helps. I had what I thought was bad RAM (broken glass sound) until I reseated, only to discover that it was actually fine.
Lastly, there seems to be idiosyncrasies from machine to machine regarding PCI slot order. Sometimes a video card won't work in a certain slot on X machine, but it will work fine on another. I've also read reports that other types of cards (Digidesign) work in some slots on some machines, but don't in others. You should shoot for the slot order as I've posted above first and foremost (the PCI Bus Master slot thing), but sometimes you HAVE to go against abiding by the Bus Master thing as noted above, either due to a video card issue, or maybe with some other type of PCI card that won't work. Sometimes your odd slot order configuration is stable for you, but not for someone else. I can't explain it, but it's definitely an idiosyncrasy from machine to machine.
I would like to think that these machines are all uniform, but from all of my experimentation on four different 9600s, and from all the years of posts at the old Digidesign forum, each 9600 seems to be its own beast.
If you can work out the small bugs in these machines, you'll have what I consider to be the best computer Apple ever released. They become rock solid once you hack the hardware as above, prune the extensions to your liking and work out the niggles.
It's my favorite computer of all time.