Board
SG3525 control modules
SG3525 control modules are common in ZX7-style inverter welders and are important for no-PWM and shutdown diagnosis.
Board role
SG3525 control modules is documented as a functional board record. A board page should answer four questions: what the board receives, what it outputs, which components control it, and which symptoms appear when it fails.
Signal and power flow
Input signal / supply
↓
Protection and feedback path
↓
Control or driver stage
↓
Output signal
↓
Connected power stage or load
Useful checks
| Check | Normal / Expected | Abnormal Meaning |
|---|---|---|
| Board supply | Stable rated rail | Auxiliary supply or connector fault |
| Enable / protection signal | Correct state for operation | Protection, VRD or feedback path is blocking the board |
| Output waveform or voltage | Changes with command | Control IC, driver transistor or load fault |
| Connector continuity | No open or burnt trace | Harness, solder joint or board damage |
Common repair direction
- Identify the board role before replacing components.
- Confirm supply voltage and ground reference.
- Check whether the board is being disabled by an external protection signal.
- Separate a bad control board from a downstream shorted power device.
- After repair, verify output with current limiting before full power testing.