The Kenwood TS-450/690S is a series of amateur radio transceivers that were popular for their versatility and performance. The TS-450 was a base station transceiver, while the TS-690S was a mobile version with a more compact design. These transceivers were known for their impressive features, including a powerful 100-watt output, wide frequency coverage (160 meters to 10 meters), and the ability to operate in various modes like AM, FM, SSB, CW, and RTTY. They also boasted advanced features like a built-in digital signal processor (DSP) for noise reduction, a large LCD display, and multiple memory channels for storing frequently used frequencies. The Kenwood TS-450/690S transceivers were highly regarded by both beginners and experienced radio enthusiasts for their robust construction, reliable operation, and intuitive controls. Their user-friendly design made them easy to set up and operate, while their wide range of features allowed for diverse applications from casual communication to more advanced amateur radio activities. However, like any complex electronic device, these transceivers can experience occasional malfunctions or require regular maintenance. This is where a comprehensive service manual comes in handy. A detailed manual provides users with the information and guidance necessary to troubleshoot and repair their TS-450/690S, saving them money and potentially extending the lifespan of their valuable equipment.