(a) Whenever such a vacancy arising from death or permanent insanity, evidenced by adjudication, occurs after disposition of the motion for new trial and appeal prayed and granted, but before the expiration of the time allowed for filing the bill of exceptions, the successor judge has and possesses the power to approve the bill of exceptions in such case if, after hearing, the successor judge finds that it fairly states the truth of the case.
(b) If such successor judge is unable to determine the truth of the case as stated in the bill of exceptions, the successor judge has the power to award a new trial to the losing party.