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| TROUBLESHOOTING & REPAIR | ||
TROUBLESHOOTING GUIDE | Observe Safety Guidelines | ||
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| detailed in the beginning of this manual. | |
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PROBLEMS |
| POSSIBLE AREAS OF | RECOMMENDED |
(SYMPTOMS) |
| MISADJUSTMENT(S) | COURSE OF ACTION |
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| WELDING PROBLEMS |
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Weld bead appears "cold." |
| 1. One or more of the machine | 1. Check for the correct open cir- |
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| settings may be wrong. Check | cuit voltage (approximately |
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| the Background, Peak Current, | 85VDC). If the correct open cir- |
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| Tailout (STT II Only), and Wire | cuit voltage IS present, the |
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| Speed controls for proper set- | Background control (R12) or |
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| tings. Adjust for optimum weld- | the Peak Current (R11) and |
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| ing performance. | associated wiring may be faulty. |
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| 2. Make sure the Wire Type and | See the Wiring Diagram. The |
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| control PC board may be faulty. | |
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| Wire Size switches are in the | |
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| Also check for loose or faulty | |
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| correct position for the elec- | |
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| connections on the heavy cur- | |
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| trode wire being used. | |
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| rent carrying conductors (i.e., | |
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| main transformer, choke, output |
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| diodes, IGBT module and out- |
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| put terminals). |
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| 2. If the correct open circuit volt- |
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| age is NOT present, perform |
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| the Switch Board Test. |
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| 3. The output diodes may be |
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| faulty. Check or replace if nec- |
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| essary. |
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| 4. The driver PC board and or |
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| control PC board may be faulty. |
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| 5. The IGBT module may be |
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| faulty. Check or replace. |
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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