TTL logic is cheap enough now... that if I've validated all works from the driver transistor to the coils... then I'd just shotgun the remaining TTL logic and replace them all. $0.75 - $3 for the peace of mind of not having to worry about the state of the logic.
Of course; I wouldn't do this for an unobtainum chip... just the common stuff like 74xx and 40xx series logic. Just my $0.02.
having said that: If your looking for some troubleshooting fun; by all means go for it.