Inside the Sony CMD-J5.
What happens under the keys?
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What happens under the keys?
Fit the components and begin with a key press.
A rubber key closes a contact in the key matrix. The baseband processor reads it and updates the LCD. A call request then passes through the radio circuit and antenna; the reply returns through the receive path. The service manual separates those transmit and receive slots. Opening the layers on this jig lets you inspect the battery, board, LCD and keypad as the local sequence advances.
Scaled Sony CMD-J5-inspired teaching cutaway based on service manual 9-873-704-24; simplified shapes and a service jig replace exact manufacturing dimensions. Its schematic flex connections stay attached during inspection. The local call sequence sends no real call. Battery energy uses an illustrative 1 Wh full charge. Radio transmit and receive are separate time slots.
Trace a key press, display update, transmit burst and received reply.
Trace a key press through display, transmission and reception.