Step 1: Locate the general direction of the problem based on the finished product
First, check if there are any defects in the produced finished products to quickly pinpoint the fault area:
1. If there are paper breaks, uneven paper roll tension, or uneven edges: Prioritize checking the tension control, slitting blade, and paper feed rollers.
2. If the finished product has normal roll tension but large dimensional deviations: Prioritize checking the meter counting system, encoder parameters, and length settings.
3. If it cannot start/has no response: Directly check the power supply and electrical control system.
Step 2: Categorize and refine the troubleshooting to quickly pinpoint the specific fault
1. Electrical system fault troubleshooting
First, check the indicator lights: If the power light is not on, prioritize checking the power input, bridge rectifier, and 7805 voltage regulator (these are the most frequently damaged components on the rewinder circuit board; refer to common faults of photoelectric protection failure).
If the DC unit reports a fault: Directly check for short circuits at the input and output terminals, check for overcurrent and undervoltage, and confirm whether it is a wiring problem or a fault in the unit itself.
Communication faults: First, check if the parameter settings are correct, then check if the terminal resistor value is normal, and finally check if the cable laying is interfering with the power line.
2. Troubleshooting Unstable Tension/Paper Breakage
First, check if the tension sensor has a signal output. Then, check if the parameter settings match the paper weight. Finally, check if the paper feed rollers are stuck or worn.
If paper breaks occur frequently during acceleration and deceleration, directly check if the acceleration/deceleration curve parameter settings are reasonable.
3. Troubleshooting Mechanical Paper Feeding
Paper Deviation: First, check if the deviation correction device is working properly. Then, measure if each paper feed roller is parallel. Finally, check if the paper roll itself is eccentric.
Uneven Cutting: First, check if the blades are worn and need replacement. Then, adjust the gap between the blades and the bottom blade.
Step 3: Directly Match the Fault Symptoms
Most common faults have fixed causes, which can be matched to the following:
1. Photoelectric protection malfunctions, but still fails after replacing the bridge rectifier: Directly check the 7805 voltage regulator. It's basically because it's short-circuited, causing repeated damage to the bridge rectifier.
2. Still not working after replacing new components: Immediately check if the wiring is loose, short-circuited, or if any components are missing.
3. Sudden shutdown/power failure: Immediately disconnect the main power supply, clean up the remaining paper, and finally check if the circuit has tripped due to overload.
