That is correct but if you want to add the support chips also...

U15, u16, clock circuit fails a lot. Usually it is u15. Check p3 and p37 of the cpu for clock running around 0.680 mhz i think is. 7437 is a good u15 replacement.

VUA2 has to be valid as well for the cs pin on the U6. That involves some more support chips. That is much less likely to the problem though. You can check at the cs pins of u6 which may be different on what type of rom/eprom you are using. U6 P20 on a 2732 eprom would be connected to U18 and needs to be valid. U6 P18 would be connected to U17 as well.

Only plug in the cpu chip. scope out every address and data pin at the u6 socket. The CS pins should be active in tihs state too so you can check them.