HP Printers serial numbers are located on the inside cover of where the toner cartridge sits.
FEQ numbers are on silver or red stickers generally on the face or top of the printer. They are preceded with the letters "FEQ" followed by a 5-digit number. FEQ numbers are mandatory to submit a supply or service request to Fisher's support.
Without an FEQ# a printer request will be addressed with IT Site Client Services to determine how to resolve problems.