keep the Property in good and serviceable repair and condition (fair wear and tear excepted) and replace all missing, damaged or broken parts with parts supplied or recommended by the original manufacturers of the Property or with parts of a quality and value such that the condition of the Property would not be materially and adversely affected, and pay all repair and operation expenses, including, where applicable, the cost of replacement of any part of the Property or otherwise, provided however that the Lessee shall not have or be deemed to have any authority to pledge the Lessor's credit or create any encumbrance upon the Property;