1. First, disassemble the membrane switch panel and peel off the top layer of the keypad membrane. Use a multimeter to identify the connection points between each key switch and the circuit board, ensuring the modified switch connections correspond to the original ones;
2. Using a positioning cone, mark and drill holes on the metal plate at each switch point on the base film. The drilled holes should be slightly larger than the actual dimensions of the miniature switch button pins to ensure unimpeded vertical movement within the holes. Undersized holes may impair switch elasticity, causing malfunction;
3. Verify the spacing between each micro-switch hole on the circuit board. Secure the micro-switches to the PCB and connect wires to their respective terminals. Simultaneously, allow sufficient PCB edge clearance to accommodate the switch board between the metal plate and display panel. As the new switch board sits between the metal plate and indicator display panel, corresponding holes must be drilled in the PCB to align with the indicator positions on the display panel. This ensures the indicator lights on the display panel can pass through the printed circuit board and be visible from the front panel. Maintain adequate clearance between the wiring and both panels to prevent short circuits.
4. Insert the fabricated printed switch board into the corresponding holes of each pushbutton switch and metal plate, ensuring the top of the pushbutton stem is flush with the metal plate surface. If protruding excessively, the outer panel film may compress the switch upon reapplication, rendering it inoperable. If too low, manual pressing may fail to engage the switch. After embedding the switch board, level it with rubber pads before reattaching the outer protective film to the metal plate. This completes the modification process. The modified switch board offers excellent tactile feedback. Pressing the buttons produces a distinct metallic click, providing an intuitive tactile feedback of the switch's on/off state. It offers extended service life, high reliability, and straightforward maintenance. Should any switch malfunction during use, the condition can be readily assessed by the click sound of the membrane switch's spring-loaded contact, enabling prompt replacement.
