The provided information appears to be a mischaracterization of the product. "Sony HCD-D90AV/GR10AV/RX100AV" refers to a series of car audio systems manufactured by Sony during the late 1990s and early 2000s. These were popular aftermarket car stereos known for their sleek design, powerful sound, and advanced features for the time. They likely included features like CD players, AM/FM radio, cassette players (in some models), and potentially even early versions of MP3 playback. The "Service Manual" referenced is not a vehicle manual but a detailed guide for technicians to understand the internal workings of these specific Sony car audio systems. It would contain information on disassembly, wiring diagrams, parts lists, troubleshooting procedures, and other essential details for repairing and maintaining these audio systems. The service manual's content would not be intended for general car owners. Instead, it would be used by trained technicians working in automotive repair shops or specialized audio installation centers. The manual's purpose would be to help them diagnose and address issues that might arise with the Sony HCD-D90AV/GR10AV/RX100AV car audio systems. It would provide a comprehensive resource for understanding the system's components, their functionality, and the steps required to repair or replace them effectively. The fact that the manual is in PDF format suggests that it would be a digital document accessible on computers or tablets, making it convenient for technicians to access and navigate during repairs.