The Snapdragon 660 (SDA660) is the heart of the device. The schematic illustrates the connections between the processor and virtually every other component—RAM, storage (eMMC/UFS), and peripherals. This section is complex, featuring high-speed data lines that require an oscilloscope to diagnose properly.
A typical Nokia 7 Plus schematic PDF is 40-60 pages long. Here are the critical pages you should bookmark: nokia 7 plus schematic diagram