In case any voting machine used in any election district shall, during the time the polls are open, become injured so as to render it inoperative in whole or in part, the managers shall give immediate notice thereof to the board of voter registration and elections or other electoral board, and such board of voter registration and elections or other electoral board shall, if possible, substitute a machine in good order for the injured machine, and at the close of the polls the record of both machines shall be taken and the votes shown on their counters shall be added together in ascertaining the results of the election. If no other machine is available for use at such election and the injured one cannot be repaired in time to continue use thereof at such election, unofficial ballots made as nearly as possible in the form of the official ballots may be used, received by the managers of election, placed in a receptacle in such case to be provided by the election officials and counted with the votes registered on the voting machine, and the result shall be declared as though there had been no accident to the voting machine. The ballots thus voted shall be preserved and returned with the statement of canvass with a certificate setting forth how and why they were voted.