This manual is applicable to maintenance personnel who do not have dedicated debugging instruments and equipment. Maintenance personnel use digital or pointer multimeters for measurement and repair. Analyze the cause of the failure through the failure phenomenon and measurement data, determine which components are damaged, and find a solution.
After the welder fails, first remove the machine housing and check the interior for any scorching or burning.
Focus on the following parts:
(1) Top section of the board: MOSFET, Control Module, Drive Module, Auxiliary Power Supply
(2)Board bottom section: Electrolytic capacitor, high voltage silicon grain, thermistor, varistor. If burning or burning is discovered, the board can be replaced directly.
Chapter 1 – Manual Arc Welding Series
Problems solution
The switch power indicator does not light, the fan does not rotate, there is no welding output
1. Confirm that the power button is closed.
2. Confirm that the input cable is connected to an electrical power source.
The power indicator lights up, the fan does not rotate, there is no welding output
1. It may be due to the input being connected to a 380V power supply, causing the overvoltage protection circuit to initiate. Change to a 220V power supply and restart the machine.
2. Unstable 220V power supply (input wire too thin or too long) or input wires overlapping the mains, causing the overvoltage protection circuit to start. Increase the diameter of the input wires and tighten the connection points. This phenomenon can be resolved by turning off the machine for 5 to 10 minutes before restarting it.
3. Continuous opening and closing of the power switch in a short period of time causes the overvoltage protection circuit to start. Unplug the machine for 5 to 10 minutes before restarting it to restore normal operation.
4. The wire between the power switch and the power board is loose. Tighten it again.
5. The 24V relay on the power board is not energized or damaged. Check the 24V power supply and relay. You can replace the relay with another relay of the same model.
The fan rotates, the welding output current is unstable or not controlled by the potentiometer, the current is sometimes large and sometimes small
1. 1K potentiometer may have quality problems. It must be replaced.
2. Poor contact at various connection points, especially connectors, needs to be checked.
The fan rotates, the abnormal indicator does not light, there is no welding output
1. Check whether several internal connection lines are in poor contact.
2. There is a break or poor contact at the output terminal connection point.
3. Use an instrument to measure the voltage from the power board to the MOS board (VH-07 connector), which should be around DC 308V.
(1) If the silicon bridge is broken or the connector has poor contact.
(2) Replace the individual leaky electrolytic capacitors (about 470UF/450V) among the four large ones on the power board.
4. If the green auxiliary power supply indicator on the MOS board does not light, contact your dealer or company.
5. For control circuit problems, contact the dealer or company.
The fan rotates, the abnormal indicator lights up, there is no welding output
1. It can be overcurrent protection. Turn off the machine and wait for the abnormal indicator to go out before restarting the machine to restore normal operation.
2. It can be overheat protection. Wait 5 to 10 minutes for the machine to recover naturally.
3. It may be a fault in the inverter circuit: disconnect the power plug from the main transformer of the MOS board (near the VH-07 fan) and restart the machine:
(1) If the abnormal indicator is still lit, the individual MOSFETs on the MOS board may be damaged. Find and replace them with the same type of MOSFETs.
(2) If the abnormal indicator does not light up.
A. The intermediate transformer may be damaged. Use a bridge to measure the primary inductance and Q value of the main transformer. The primary is in parallel, L=12.2-2.0mH, Q>40. If the inductance and Q values are too small, they must be replaced.
B. Some rectifier tubes in the transformer secondary may be broken. Search and replace rectifier tubes of the same type.
4. It could be a fault in the feedback circuit.
5. Troubleshooting common problems for ARC 250, ARC 315, ARC 400, ARC 400B, ARC 500
The meter head is not displayed, the fan does not rotate, and there is no welding output
1. Confirm that the air switch is closed.
2. The input cable is connected to a power source with electricity.
3. The thermistors (4) are damaged (the normally open point of the 24 V relay does not close or the contact is bad).
4. Power board (bottom board failure, no output voltage DC 537V):
(1) The silicon bridge is broken and the silicon bridge connector has poor contact.
(2) The power panel has abraded or burned areas.
(3) Check the connection line from the pneumatic switch to the power board and the connection line from the power board to the inverter board (MOS board).
5. The auxiliary power supply part on the control board fails. (Contact the dealer or manufacturer)
The meter head is displayed normally, the fan rotates normally, and there is no welding output
1. Check whether several internal connection lines are in poor contact.
2. There is a break or poor contact at the output terminal connection point.
3. Inverter circuit failure (abnormality indicator lights up)
Disconnect the power line from one of the inverter boards (near the VH-07 connector on the front panel) and the power line from the transformer (near the VH-07 connector on the fan) and restart the machine:
If the abnormal indicator does not light up, the fault is in this inverter, otherwise the fault is in the other inverter. Then turn off the power, connect the faulty inverter power line (do not connect the main transformer power line), and restart the machine:
1) If the abnormality indicator does not light up, the fault is in the intermediate board;
The. The intermediate transformer may be damaged. Use a bridge to measure the primary inductance and Q value of the main transformer, and measure each transformer separately. If the inductance or Q value is too small, replace it.
B. Some rectifier tubes on the intermediate plate may be damaged. Replace them.
2) If the abnormal indicator lights up, the fault is in the MOS board and some of the inverter's MOSFETs are damaged. Replace them with the same type of MOSFETs.
4. Feedback circuit failure (abnormality indicator lights up). Contact the dealer or manufacturer. Large welding spatter, irrational output polarity connection, switch the output electrode polarity.
Chapter 2 – TIG Welding Series
1. The power switch is on, but the green light does not light, the fan does not rotate, and there is no response inside the machine when the welding gun switch is pressed.
• Cause analysis:
1. The external power supply is abnormal.
2. The power cord is broken or the connector is bad.
3. The power switch is damaged.
• Problems solution:
1. Check external voltage of 220 V/AC.
2. Check the connectors.
3. Replace the power switch.
2. The power switch is on, the green light does not light, the fan rotates, and there is no response inside the machine when the welding gun switch is pressed.
• Cause analysis:
1. The power button on the bottom board connector is not connected properly.
2. The auxiliary power supply on the top board is damaged and there is no DC 24V output.
• Problems solution:
1. Check the connectors.
2. Repair or replace the auxiliary power supply.
3. The green light turns on after turning on the machine, the fan rotates, but there is no response when pressing the welding gun switch.
• Cause analysis:
1. The welding gun switch or control line is loose.
2. Poor aviation socket contact or disconnected connection wire.
• Problems solution:
Check and replace.
4. After starting the machine normally, there is gas output when pressing the welding gun switch, but the red light does not light and there is no high frequency.
• Cause analysis:
Firstly, check the output end of the welder, disconnect the high frequency control line and see if there is a no-load voltage DC 55V. If there is a DC 55V, see if it can arc.
If it can form an arc, focus on checking the initial part of the high-frequency arc:
1. Whether the connection line of the booster transformer from the top plate to the bottom plate is loose or the transformer is open circuit.
2. Whether the high voltage silicon grain and 102/10KV high voltage capacitor are damaged.
3. If the high voltage discharge nozzle is sticky, the gap is too large or the surface is severely oxidized.
4. Whether the high frequency arc starter and connector are loose.
5. Whether the high-frequency control relay is damaged and the power circuit is normal.
6. Whether the switch with ARC/TIG conversion function is good. If there is no DC 55V output, check whether the inverter circuit works normally:
① Whether the control module has a drive signal output.
② Whether the conversion and driving modules work normally.
③ Whether the connection line of the field tube, main transformer and main current is loose.
• Problems solution:
1. Check and replace.
2. Check and replace.
3. Adjust or replace.
4. Check and replace.
5. Check and replace.
6. Check and replace.
5. After starting the machine normally, there is gas output when pressing the welding gun switch, but the red light is on.
• Cause analysis:
1. Overcurrent protection during operation.
2. Protection against overheating during operation.
3. There may be a fault in the inverter circuit and arc starting part. (After power off, disconnect the power plug from the arc starting transformer on the MOS board (near the VH-03 fan) and turn on the machine by pressing the welding gun switch.
The. If the red light does not come on, it is a short circuit in the arc starting transformer or it could be the reinforced arc starting and the diode breaking.
B. If the red light comes on, there is a problem in the inverter circuit. Turn off and disconnect the power plug from the intermediate transformer (near the VH-07 fan), and turn on the machine by pressing the welding gun switch.
w. If the red light turns on, some of the MOSFETs on the inverter board are damaged, and at the same time, check the drive module components for any damage.
d. If the red light does not light up, there is a short circuit in the intermediate transformer or rectifier tube. The inductance and Q value of the transformer can be detected using a bridge. C=0.9-1.6mH, Q>35, and each rectifier tube should be checked and deleted one by one.
• Problems solution:
1. Turn off the machine for 5 minutes and turn it on again.
2. Stop working for 5 minutes.
The. Replace the; B. Check and replace; w. Check and replace; d. Replace if too small.
6. The machine turns on normally, it may form an arc, but the welding point turns black.
• Cause analysis:
1. Check whether the solenoid valve and its air tube are blocked by foreign objects.
2. The solenoid valve is damaged.
3. The solenoid valve power supply control circuit is damaged.
4. Remove the welding gun, press the welding gun switch, if there is gas output, it means the welding gun is damaged or leaking gas.
5. Poor current carrying capacity of the welding gun cable, causing arc dispersion or deviation.
6. Poor quality tungsten electrode or impure argon gas.
• Problems solution:
1. Clean.
2. Replace.
3. Check and replace.
4. Replace.
5. Replace.
6. Replace.
7. The welding current is unstable and uncontrollable, sometimes large and sometimes small.
• Cause analysis:
1. Bad or damaged potentiometer contact.
2. Leakage or damage to the bottom plate filter capacitor.
3. The input or output cable is too long or thin, causing unstable current.
4. Bad contact or loose connector.
• Problems solution:
1. Check and replace.
2. Check and replace.
3. Increase the cross-sectional area of the conductor.
4. Check and replace.
8. The machine trips when turned on.
• Cause analysis:
1. Short circuit of the rectifier silicon bridge.
2. Loose and short-circuited power cord.
• Problems solution:
1. Replace.
2. Connect securely.
9. When pressing the welding gun switch, the gas valve closes immediately and without delay, and the sealing wave is slow.
• Cause analysis:
The IN4004 diode for powering the gas valve control relay is short-circuited.
• Problems solution:
Check and replace.
10. There is a high-frequency discharge sound when pressing the welding gun switch, but there is no current output.
• Cause analysis:
1. Weak or loose contact of the welding gun ground wire.
2. The ground wire output terminal and pneumatic joint are loose or the connection to the intermediate plate is loose.
• Problems solution:
1. Check and replace.
2. Check and replace.
11. Arc ignition is not good.
• Cause analysis:
1. The gap between the discharge nozzle is too large or too small, or the surface is oxidized.
2. The capacity of the high voltage output capacitor is low and there is a short circuit at the high voltage.
3. Dust in the arc starter causes leakage between turns.
4. Poor quality argon gas or tungsten electrode.
5. The welding gun has a loose connection.
• Problems solution:
1. Clean and adjust.
2. Check and replace.
3. Check and replace.
4. Check and replace.
5. Check and replace.
12. When starting the machine, the red light comes on immediately after starting work.
• Cause analysis:
1. The negative feedback loop is open.
2. Poor contact of main current transmission circuit or power device causes overcurrent protection.
• Problems solution :
1. Check the connection.
2. Check and replace.
13. High frequency occurs when starting the machine.
• Cause analysis:
1. The manual switch control optocoupler PC817 (or transistor 8050) is damaged.
2. Short circuit in welding gun switch or control line.
• Problems solution:
1. Check and replace.
2. Check.
14. High frequency occurs continuously during welding.
• Cause analysis:
1. The high frequency control relay is damaged.
2. There is spike interference in the output voltage.
3. High frequency automatic locking.
• Problems solution:
1. Replace.
2. Tighten the feedback and control line.
3. Increase the absorption of the high-frequency transformer and increase the capacitance at the coil end of the high-frequency relay.
