INTRODUCTION Kenwood's TS-520 is a solid-state, amateur band single side band transceiver which uses only three vacuum tubes in the exciter and final stages. The TS-520 incorporates many sophisticated and modern features which make it a very useful transceiver. The information included in this service manual is intended to complement the technical data supplied in the operator's manual. For example the operator's manual includes pictorial parts displays, voltage tables, operating instructions, a troubleshooting chart, and the block diagram. This service manual includes technical service procedures, a parts list, circuit board layouts and full schematics. Together, the two publications provide full technical information.