its the solder on the CPU card that has cracked/failed.

If i push on the CPU card while the machine is booting, i get an instant system error of either address error, bus error, or illegal instruction.

then it doesnt boot again.

but if i take and put some force on the CPU itself alone, only, it boots everytime, straight into OS9 and no more cache errors.

problem found. once i head into the shop tomorrow, ill toss it on the reflow bench and give it a whirl.