Model family
Chui Shui 200EP / 350EP / 500EP Inverter TIG Welders Repair Reference
Repair-reference hub for Chui Shui / Chin Shui EP-series inverter TIG machines, focused on IGBT failure recovery, trigger-board evidence, low-risk testing and calibration.
Database summary
This WelderData model-family record covers Chui Shui / Chin Shui 200EP, 350EP and 500EP style inverter TIG / EP welding machines as a repair-reference family. The useful repair content is not a sales description of the machine. It is the staged procedure after an IGBT failure, the trigger-board offline test, gate-lead checks, high-frequency absorption checks, low-voltage current-limited testing and final calibration sequence.
The 500EP failure path is especially useful because a new IGBT can be destroyed again if the trigger board, gate wiring, main transformer, secondary fast rectifier, high-frequency absorption capacitors or feedback calibration are not checked first.
Platform areas to separate
| Area | Repair evidence | Why it matters |
|---|---|---|
| Main power path | Three-phase rectifier, IGBT module, main switching transformer, secondary fast rectifier and output path. | A visible IGBT failure may be the endpoint of a transformer, secondary diode or absorption fault. |
| Trigger board | CN1 supply, CN2 command line, CN7/CN8 gate output, UC3706 driver evidence, R36–R39 gate resistors and ZD1–ZD8 clamps. | Bad trigger evidence can make a replacement module fail immediately. |
| Gate wiring | Two groups of IGBT gate-signal leads, connector tension and branch continuity. | Poor gate-lead contact can create false triggering and primary-side short failure. |
| HF absorption circuit | Small absorption capacitors, shorts, loss of capacitance and evidence of HF feedback into boards. | Failed absorption parts can damage both the power section and control PCB. |
| Calibration / feedback | VR1–VR7 sequence, CO / CC signals, min-current, max-current and overcurrent settings. | The machine may appear repaired but operate outside the safe current or protection range. |
Model frequency and feedback references
| Model | Working-frequency reference | Primary feedback resistor note |
|---|---|---|
| 200EP | About 45us period class. | 100Ω / 5W class primary feedback resistor. |
| 350EP | About 50–55us period class. | 100Ω / 5W class primary feedback resistor. |
| 500EP | About 55–60us period class. | 47Ω / 5W class primary feedback resistor. |
Use these values as model-family repair clues, not as a universal setting for unrelated machines.
200EP / 350EP / 500EP timing and service differences
The EP series shares a repair logic, but the working-frequency reference should be recorded by model class. Use the timing evidence together with trigger-board output symmetry, gate-lead contact and power-stage isolation.
| Model class | Timing reference | Service meaning |
|---|---|---|
| 200EP | About 45µs | Compact EP-class board timing reference; do not compare directly with 500EP without noting model class. |
| 350EP | About 50–55µs | Intermediate EP-class timing range; record actual period before replacing a trigger board. |
| 500EP | About 55–60µs | High-power EP-class reference; use with staged low-voltage and resistor-load validation after IGBT failure. |
EP-series service note
When a 200EP, 350EP or 500EP machine has suffered IGBT failure, treat the model page as an entry point only. The actual repair path should continue into the 500EP staged sequence and trigger-board calibration page so the board evidence, gate-path evidence and main-loop evidence are recorded separately.