QUESTION: If a member sends in a blank ballot, does it count toward quorum?

ANSWER: Yes, abstentions and blank ballots count toward quorum. Civil Code §1363.03(b). Ballots with invalid write-ins (such as Mickey Mouse, "Remove the Board" or any other issue not on the ballot) also count toward quorum. If a ballot contains a mix of valid and invalid votes, the valid votes are counted and the invalid ones ignored. (Robert's Rules, 10th ed., p 401.)