One of our aluminum foil re-winding machines experienced a failure in its photoelectric protective function. After emergency treatment, the machine remains operational; however, due to the absence of protective detection, operators are concerned about personal safety, leading to reduced work efficiency.

Disassembled the circuit board for visual inspection and found that the substrate around the power bridge had changed color, determining that the bridge was burnt out. After replacing the bridge and applying power, the vehicle still showed no response. Using a multimeter, it was discovered that the newly replaced bridge was also burnt out, indicating a short circuit. By individually inspecting components from the bridge downwards, a three-terminal voltage regulator (7805) was found to be punctured. After purchasing new components and replacing them, the power indicator light on the circuit board illuminated upon applying power.

(1) Conducted a thorough inspection and adjustment of the bearings, and carefully verified the coaxial alignment of the couplings. Checked and gradually adjusted the loosening of the foot bolts. Repaired or appropriately replaced the defects that occurred in individual parts during operation.

(2) The paper re-winder was disassembled for a major overhaul, with the rotor and all components removed and cleaned. A thorough inspection of all internal parts was conducted, measuring wear and erosion levels, and replacements were scheduled regularly as needed.