The review by the court shall not be extended further than to determine, based upon the entire record which shall be certified by the appeals board, whether:
(a) The appeals board acted without or in excess of its powers.
(b) The order or decision was procured by fraud.
(c) The order or decision was unreasonable.
(d) The order or decision was not supported by substantial evidence.
(e) If findings of fact are made, such findings of fact support the order or decision under review.
Nothing in this section shall permit the court to hold a trial de novo, to take evidence, or to exercise its independent judgment on the evidence.
(Added by Stats. 1973, Ch. 993.)