(SEL C, D, E, F, the chip selects for UD6-UD9), that's fine
To check the data bus lines between all of the PROMs and the CPU, How about continuity between:-
Code:
CPU UD6-UD9 pins
26 9
27 10
28 11
29 13 *note the jump 11-13
30 14
31 15
32 16
33 17
And to check the address line connections from the address buffers to the PROMs,
Code:
UC3 UD6-UD9 pins
18 8
3 7
16 6
5 5
14 4
7 3
12 2
9 1
UB3 UD6-UD9 pins
18 23
3 22
16 19
5 18