The Transformer is an OEM component specifically designed for GE microwaves. It acts as the essential electrical converter that receives normal household current and steps it up into the precisely controlled high voltage needed to power the magnetron tube. During use, the transformer transmits regulated H.V. output to ignite the magnetron and generate safe microwave energy for cooking. Causes of a bad transformer include wear from long-term heat cycling strains and potential pinhole leaks developing over many years of service.  Symptoms of a bad transformer include: Magnetron failing to ignite or running intermittently Portions of foods not heating thoroughly on lower power levels   Electrical buzzing or burning smells detected Microwave slowly losing full power ability over time This OEM GE replacement is compatible with Hotpoint, RCA and select Kenmore microwave models as well.WB27X11024 (AP4362860) replaces 1474109, AH2339850, EA2339850, PS2339850.