Test power devices and DC bus short path.
Board reference
CT-312 Top Inverter Board Reference
A top-inverter-board service reference for CT-312 switching and power-device diagnosis.
Quick Answer
The CT-312 top inverter board is the switching and drive layer. It should be checked for power-device failure and drive permission after bottom-board supply and middle-board output evidence are separated.
- Use this page for power-device short, no switching, drive transformer or control-module symptoms.
- Do not use it as the first page for no gas or no HF symptoms.
- Repeated MOSFET/IGBT failure requires checking drive and load evidence before replacing devices.
CT-312 top inverter evidence
| Function | Board-side evidence | Related symptoms |
|---|---|---|
| Power devices | MOSFET / field-effect tube or switching device area. | Breaker trip, power-device short, no switching. |
| Driver transformer | Gate-drive isolation/drive transfer. | No switching, weak or missing drive. |
| Control module | Switching permission/control section. | Fan/gas/HF may work but no inverter output. |
| Board supply / indicator | Supply and power indicator path from lower board. | Indicator on with no output; supply missing to top board. |
Top-board diagnostic split
Power-device evidence should be confirmed with driver and output-load evidence.
Check drive transformer and control-module permission.
Check board supply, drive output and main transformer path.
Run IGBT/MOSFET replacement precheck before full power.
Related records
Use these to avoid repeat failure.