Got this Super Burger Time PCB (by Data East) for a repair:
Board played fine except for the fact the BLUE color was totally missing hence the yellowish screen:
Palette RAMs are two 2K x 8-bit devices, both were Sony CXK5814 (6116 compatible) which are well known to be unreliable:
Probing them revealed that the one @9K had all data lines stuck low while address were happily toggling (on left of the below picture)
The IC was most likely bad so I removed it:
The out-of-circuit confirmed it:
Replacing it fixed the board completely.