Using this manual This service manual contains information necessary to test, maintain, and service the following: HP Designjet T120 Basic Printer 24 inch CQ891A HP Designjet T520 Pro Printer 24 inch CQ890A HP Designjet T520 Pro Printer 36 inch CQ893A For information about using these printers, see the user's guide. Readership The procedures described in this service manual are to be performed by HP Certified service personnel only. Part numbers Part numbers for printer service parts are located in Parts and diagrams on page 119 . ENWW v