The good thing about having a board issue with lamp and switch related stuff is that you can work your way through with a dmm and test the good vs the bad to see which part is not giving the same readings as the working portion. Testing resistors "effectively" within a circuit is next to 'not gonna happen'. I would check the good segment for the quantity of resistance and continuity and compare to the supposed bad segment. What is measuring off? If you find that all components are measuring the same then I would say your issue lies within the corresponding IC's. 7406 TTL chips at 11F and 12E drive the rows though a series of 2N5060 controlled rectifiers at Q81 to Q88. These also connect to the 6821 PIA at 11D.