I still need to make time to send my Virtua Fighter 3 pcb to him but I still don't have the wires to even run a model 3it depends WHY, if he determined the CPU is bad and doesn't have a replacement then someone with a CPU could fix it (or if you sourced one Ken could fix it)
but if it's bad because CPU pin traces got ripped off the board, then it might be really ugly to fix or near impossible to fix.
Part of what makes Ken so well regarded is that he stands behind his work, and his work stands the test of time. So a lot of times when the only fix is an ugly and fragile fix he'll say no. Doesn't mean it can't be done, it just means he's not willing to risk his reputation on the fix holding up.