Diagnostic workflow
MIG / MAG Brand-Series Fault Reference
Brand-series diagnostic routing for KR-style, OTC X-series, NBC/NB and similar CO2/MIG/MAG welders.
Database summary
This WelderData diagnostic page routes MIG/MAG brand-series faults after the generic symptom has already been identified. It is intended for machines where the technician must decide whether the fault belongs to the feeder harness, torch command, gas circuit, crater-fill/burn-back path, remote/local interface, voltage-control circuit or welding power source.
The page should be used with the general MIG/MAG fault routing page and the six-wire feeder table. Brand names are treated as repair-pattern references rather than as exact single-model service instructions.
Brand-series routing table
| Machine family / pattern | Useful diagnostic focus | Common wrong path |
|---|---|---|
| Panasonic KR-style CO2/MIG | Feeder interface, voltage command, crater-fill and burn-back timing | Replacing power devices before checking feeder command and stop sequence. |
| OTC X-series style MIG/MAG | Remote/local control, gas/feeder/power-source command separation | Assuming wire feed proves the voltage control section is healthy. |
| NBC / NB generic CO2/MIG | Torch command, gas valve, wire motor, voltage control and protection enable | Treating every no-feed symptom as a motor failure. |
| Power Compact style small MIG | Torch switch, feeder board, thermal/protection state and output contactor | Ignoring protection or power-source enable when the wire motor runs. |
Stop-sequence and control-interface symptoms
| Symptom | First checks | Related page |
|---|---|---|
| Wire sticks in the weld pool at stop | Burn-back time, voltage-off timing, wire motor stop timing | Wire-feed / voltage control |
| Wire burns back into contact tip | Burn-back too long, feeder stop sequence, voltage remaining after feed stop | MIG / MAG fault routing |
| Panel voltage knob has no effect | Remote/local switch, feeder-side control line, command voltage path | Panasonic KR-style reference |
| Feeder control works but main unit does not respond | Interface connector, command return line, machine/feeder authority selection | OTC X-series reference |
Workflow
- Start from the visible symptom: no gas, no feed, no arc, unstable arc, fixed voltage or poor stop sequence.
- Check whether the torch command reaches the feeder and the power source.
- Separate gas valve action from wire-motor action; one can work while the other path is faulty.
- Separate wire-feed speed command from welding-voltage command.
- For stop faults, check crater-fill and burn-back logic before replacing the wire-feed motor.
- Only move to the main power stage after command, interface and protection evidence has been collected.