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| TROUBLESHOOTING |
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| Observe all Safety Guidelines detailed througout this manual | |||||
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| PROBLEMS |
| POSSIBLE CAUSE |
| RECOMMENDED | |
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| (SYMPTOMS) |
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| COURSE OF ACTION | ||
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| FUNCTION PROBLEMS |
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| H. Machine trips off when under no | 1. Power bridge rectifier may have | 1. | Refer to Power Hybrid Bridge | |||
| load or makes excessive noise |
| a shorted diode or SCR. |
| Checking Procedure. See | ||
| like it is loaded. |
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| Troubleshooting Procedures – | ||
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| Checking Snubber Circuit and | |
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| Power Rectifier Bridge Assembly. | |
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| 2. | Short in the transformer. | 2. | Repair. | |
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| 3. | Fan hitting vertical baffle. | 3. | Clear the fan. | |
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| I. Variable or sluggish welding arc. | 1. Poor work or electrode cable | 1. | Check and clean cable connec- | |||
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| connection. |
| tions. | |
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| 2. | Current too low. | 2. | Check recommended currents | |
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| for rod type and size. | |
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| 3. | Welding leads too small. | 3. | See Troubleshooting Procedures | |
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| – Fault Protection Operation. | |
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| 4. | Open SCR or diode in power | 4. | Check per Power Hybrid Bridge | |
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| rectifier bridge. |
| Procedures. See | |
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| Troubleshooting Procedures – | |
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| Checking Snubber Circuit. | |
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| 5. | Control circuit problems. | 5. | See Troubleshooting | |
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| Procedures. | |
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| J. Welder will not shut off. | 1. Input contactor contacts frozen. | 1. | Replace input contactor. | |||
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| K. Current control on machine not | 1. Current control switch in wrong | 1. | Place switch in “machine” posi- | |||
| functioning. |
| position. |
| tion. | ||
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| 2. | Current control switch defective. | 2. | See Troubleshooting Procedures | |
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| – Toggle Switch Check. | |
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| 3. | Current control potentiometer | 3. | See Troubleshooting Procedures | |
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| defective. |
| – Checking Current Control | |
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| Rheostat. | |
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| 4. | Lead or connection in control | 4. Repair or connect. | ||
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| circuit open. |
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| 5. | Defective control or circuit | 5. | See Troubleshooting Procedure | |
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| boards. |
| – Power Silicon Controlled | |
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| Rectifier. | |
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CAUTION
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
E500
