I. Power System Faults
1. Abnormal Input Power
Symptoms: Power indicator light is off, equipment is unresponsive, leakage current circuit breaker trips.
Causes: Damaged power cord, blown circuit breaker, input voltage mismatch (e.g., 380V mistakenly connected to 220V).
Solutions: Check the power cord resistance (should be <0.5Ω), replace damaged cables; check if the circuit breaker's rated current matches; confirm the voltage label matches the actual input, and install a voltage regulator if necessary.
2. Internal Power Module Fault
Symptoms: Indicator light is on but there is no output voltage.
Causes: Rectifier bridge breakdown, filter capacitor failure, damaged switching power supply chip.
Solutions: After disassembling the equipment, check the forward and reverse resistance of the rectifier bridge (normally it should alternate between infinite and several hundred ohms); replace capacitors with those of the same specification (e.g., 470μF/400V electrolytic capacitors must have strictly matched voltage ratings); use a hot air gun to replace damaged power supply chips.
II. Control Circuit Failure
1. Drive Circuit Failure
Symptom: Fan runs but no welding current.
Cause: Damaged IGBT drive optocoupler, deteriorated drive resistor, or malfunctioning protection circuit.
Solution: Use an oscilloscope to check the drive signal waveform (normally a 15-25kHz square wave); replace the drive resistor with one of the same parameters (a metal film resistor is required to ensure stability).
2. Abnormal Parameter Display
Symptom: Abnormal parameter display and cannot be adjusted.
Cause: Data loss in the EEPROM memory chip, crystal oscillator frequency offset, or reset circuit failure.
Solution: Rewrite the main control program using a programmer (original parameters must be backed up); replace the crystal oscillator with one of the same frequency and calibrate the system clock; calibrate the parameters (adjust the current/voltage display values using a standard load, error ≤ ±3%).
III. Operating Parameters and Environmental Factors
1. Incorrect Parameter Settings
Symptom: Excessive welding current, insufficient voltage.
Cause: Operators did not master the correct parameter setting methods (e.g., the MIG welding torch angle should be maintained at 65-75°).
Solution: Ensure operators receive operational training and master the correct parameter setting methods.
2. Environmental Factors
Symptoms: Equipment overheating, poor ventilation.
Causes: High ambient temperature, operating beyond the duty cycle, long continuous working time of the welding machine.
Solution: Improve ventilation conditions and lower the ambient temperature; use the equipment according to the duty cycle to avoid overloading.
IV. Preventive Maintenance Strategy
Daily Inspection: Clean equipment dust (focus on cleaning the cooling fan and air inlet).
Monthly Maintenance: Check grounding resistance (should be <4Ω), tighten all wiring terminals.
Annual Overhaul: Replace aging capacitors (electrolytic capacitors with a lifespan of more than 5 years must be replaced).
Operational Training: Ensure operators master the correct parameter setting methods.
