This document applies to firmware version 2.4 and above. This is the service manual for the RSA3303A and RSA3308A Real-Time Spectrum Analyzers. The manual contains information needed to service the analyzer to the module level. This manual is divided into sections, such as Specifications and Theory of Operation. Further, some sections are divided into subsections, such as Product Description and Removal and Installation Procedures. Sections containing procedures also contain introductions to those procedures. Be sure to read these introductions because they provide information needed to do the service correctly and efficiently. The manual section name and a brief description of each is given below. Specifications contains a description of the analyzer and the applicable characteristics. Operating Information includes general information and operating instructions. Theory of Operation contains circuit descriptions that support service to the module level. Performance Verification contains procedures for confirming that the analyzer functions properly and meets warranted limits. Adjustment Procedures contains procedures for adjusting the analyzer to meet warranted limits. Maintenance contains information and procedures for performing preventive and corrective maintenance of the analyzer. These instructions include cleaning, module removal and installation, and fault isolation to the module. Options contains information on servicing factory-installed options. Electrical Parts List contains a statement referring you to Mechanical Parts List, where both electrical and mechanical modules are listed. Diagrams contains a block diagram and an interconnection diagram. Mechanical Parts List includes a table of all replaceable modules, their descriptions, and their Tektronix part numbers.