1. power supply problem: first, check whether the power supply is normal. You can check whether there is electricity in the socket, whether the power cord is firmly connected and whether the power switch is turned on.

2. Electrode problem: Check whether the electrode is selected correctly and installed correctly. The covered electrode shall be of a type suitable for the required welding material and shall be correctly installed in the electrode clamp.

3. Current setting problem: Check whether the current setting is correct. If the current setting is too low, enough arc may not be generated for welding. You can try to gradually increase the current setting until a stable arc can be generated.

4. Grounding problem: Check whether the grounding is good. Welding machine needs good grounding to work normally. You can check whether the grounding wire is firmly connected and whether the grounding point is clean.

5. Arc length problem: Check whether the arc length is appropriate. Too long or too short arc length may lead to arc-free welding. You can try adjusting the arc length. In general, the arc length should be kept between 2 and 4 mm. ..

6. Electrode wear: Check whether the electrode is worn. If the electrode is badly worn, it may not be able to generate enough arc for welding. You can try replacing the electrode.

7. Arc stabilizer problem: Check whether the arc stabilizer works normally. Arc stabilizer is an important part to maintain arc stability. If the arc stabilizer is damaged or fails, it may lead to arc-free welding. You can try replacing the arc stabilizer.

In a word, the above are the possible problems and solutions of arc fault of Shenyuan ZX7-200 inverter DC hand arc welding machine. If the above methods fail to solve the problem, it is recommended to contact professional maintenance personnel for maintenance.