When a Welding Machine Refuses to Weld
If your welding machine won’t weld at all, the issue may range from a simple setting error to a critical internal failure.
At Link Technical Arc Services, this is one of the top service calls we receive across Toronto and the GTA.
This article covers:
- Electrical, mechanical, and control-related causes
- Common mistakes operators make
- When DIY stops and professional repair is required
12 Common Reasons a Welding Machine Is Not Welding
1. Incorrect Polarity or Output Selection
Simple but common:
- Wrong polarity (DCEP vs DCEN)
- Stick/TIG/MIG mode mismatch
- Remote control selected without a remote attached
2. Faulty Welding Leads or Connections
Loose or damaged leads can:
- Prevent arc initiation
- Cause intermittent welding
- Create excessive heat at terminals
Always inspect:
- Output lugs
- Dinse connectors
- Ground clamp condition
3. Failed Contactor or Solenoid
A failed contactor means zero output, even though the machine appears operational.
This is extremely common on:
- High-duty cycle machines
- Dusty shop environments
- Older industrial welders
4. Trigger or Control Signal Failure
No trigger signal = no weld.
Check:
- MIG gun trigger continuity
- TIG foot pedal
- Remote selector switch
- Control cable pins
5. Control Board Malfunction
Modern inverter welders depend on PCBs to regulate output.
Signs include:
- No error codes
- Random behavior
- No response to amperage changes
These repairs require specialized diagnostic tools.
6. Thermal Protection Lockout
Some machines disable output without obvious warning.
Common causes:
- Blocked airflow
- Failed fan
- Dirty internals
- Defective temperature sensor
7. Engine RPM or Generator Fault (Engine-Driven Welders)
If RPM is too low, the machine cannot generate welding power.
Potential issues:
- Governor problems
- AVR failure
- Engine electrical faults
8. Faulty Selector Switch
Worn selector switches can fail internally while still rotating normally.
This is a silent failure we see often.
9. Internal Fuse or Breaker Failure
Some internal protection devices fail without tripping externally.
10. Moisture or Contamination
Moisture causes:
- PCB corrosion
- Short circuits
- Insulation breakdown
Common in outdoor or unheated storage environments.
11. Software or Firmware Errors
Certain newer machines may require:
- Firmware updates
- Control board resets
- Reprogramming
12. Severe Internal Component Failure
Includes:
- Transformer damage
- Inverter module failure
- Rectifier faults
At this stage, professional repair is mandatory.
Why DIY Troubleshooting Often Makes Things Worse
We frequently repair machines that were:
- Opened incorrectly
- Shorted during testing
- Reassembled improperly
This adds time, cost, and risk.
Trusted Welding Machine Repair in Toronto & GTA
Link Technical Arc Services provides:
- Brand-experienced technicians
- Accurate fault isolation
- OEM and approved replacement parts
- Emergency and scheduled service
We serve:
Toronto | Mississauga | Vaughan | Brampton | Markham | Scarborough | Oakville | GTA
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