@AmireX:
You could also try remove the motherboard fastmem, I recall some people had issues with that and the accelerator.
I guess it already has been said, but don't forget to set the busclock to external.
If that doesn't help you should check if the fragile solders of the 68060-socket are intact. To do that apply some gentle force on the 68060 with a finger (just a wee bit of force, you should definately not make the board bend!) and power up the computer while still having the finger there and see if it makes a difference.
/Patrik
