X-ray wrote:
But that's just the thing: I had a look at the connectors on the cards and the CPU slot: all perfectly clean, and the 030 worked. I think something else screwy is going on, and it bugs me that I haven't found it.
You don't necessarily have to see dirt in order for a contact to be bad. Take a memory simm for example. Clean its contacts with a q-tip dipped in isopropyl alcohol and see how black the q-tip will get after you finish cleaning. The same thing happens to the cpu slot connector due to age and constant usage, however the contact pins in this case are so delicate and fragile that the only way to clean them properly would be with a PCB contact cleaner/degreaser spray.
Don't be hardheaded about all this, trust me. Try it and see.
I'd take out the whole motherboard and spray it with a PCB degreaser, and let it dry, and especially around the area of the CPU slot. I'd even spray the accelerator cards themselves too.
I've had a problem like this in the past with an A3000D. It wouldn't detect my Warp Engine accelerator, and all the jumpering was fine. Finally, I've decided to clean the CPU slot and the card itself and viola...it worked.