Whirlpool oven/combo unit

Question

Hello, thank you for taking the time to assist me. My parents have a Whirlpool Microwave/oven combo unit. We are trying to locate the exact model number of the unit to see if we can order a new transformer for the Microwave. The model number on the door reads RM288PX803 and the serial number is XE3681197. Any assistance would be greatly appreciated.