1. Power System Faults
1. No output
Check input voltage stability (three-phase power must be balanced, with an error of ≤5%)
Test fuse status (use fast-acting fuses of the same specification)
Check main transformer coil resistance (short circuit/open circuit requires replacement)
2. Abnormal protection light illuminates
Check control board supply voltage (e.g., 14.8V on pin 4 of a 324 chip)
Check voltage on pin 16 of a 3846 chip (>0.35V will trigger a cutoff)
Repair voltage on pin 6 of an 084 chip (normal is 5.5V; abnormalities require voltage divider adjustment)
2. Output Circuit Faults
1. Output short
Check cable aging (key bends) and connector oxidation
Measure output resistance (should be <0.5Ω)
Avoid overloading (load factor ≤80%)
2. Unstable welding
Test no-load voltage (normal 50-80V)
Clean the electrode chuck (roughness <1.6μm)
Check ground wire contact (remove the oxide layer on the workpiece)
III. Mechanical and Control Failures
1. Current regulation failure
Check the displacement of the moving iron core/moving coil
Replace aging components on the control board (such as bulging capacitors) . Lubricate the transmission mechanism (use high-temperature grease)
2. Module damage
Compare and test the rectifier module (resistance difference between new and old parts) . Replace damaged 3846/084 chips . Check the voltage divider resistor (such as a 6.8kΩ + 39kΩ combination)
IV. Maintenance Recommendations : Clean the electrode contact surface every 50 hours . Install a voltage regulator of 300W or higher to cope with grid fluctuations . Use conductive paste to prevent oxidation during the rainy season
