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TROUBLESHOOTING & REPAIR | ||||||
Observe Safety Guidelines |
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| TROUBLESHOOTING GUIDE | |
detailed in the beginning of this manual. |
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PROBLEMS | POSSIBLE AREAS OF |
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(SYMPTOMS) | MISADJUSTMENT(S) |
| COURSE OF ACTION | |||
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| OUTPUT PROBLEMS |
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The output terminals are always | 1. | This is a normal condition. The |
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electrically “hot.” |
| open circuit voltage should be |
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| approximately 67VDC. | The |
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| open circuit voltage may vary |
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| with the input line voltage. |
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The machine welds but reduces to | 1. | Operating the machine beyond | 1. | Check the output shunt for | ||
a low output under load and |
| the current rating will cause the |
| loose or faulty connections. | ||
remains there until the load is |
| overload protection | circuit | on | 2. | The output shunt may be faulty. |
removed and the arc |
| the control board | to phase- | |||
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| Replace. | ||||
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| back the machine to a low out- |
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| put. |
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| 3. | The control board may be faulty. |
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| Replace. |
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The machine shuts off even when | 1. Make sure the fan motor and | 1. | Perform the SCR/Diode | |||
not under load or makes excessive |
| blades are operating properly. |
| Rectifier Bridge Test. | ||
noise like it is loaded. |
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| 2. | Perform the Main Transformer |
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| Test. |
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| 3. | Check the latching resistor R3. |
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| Normal resistance is 40 ohms. |
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CAUTION
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call