TROUBLESHOOTING GUIDE
Trouble |
| Cause |
| What To Do |
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Input contactor (CR1 chatters). | 1. | Faulty input contactor (CR1). | 1. | Repair or replace. |
| 2. | Low line voltage. | 2. | Check input power. |
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| |
Machine input contactor does not | 1. Supply line fuse blown. | 1. | Replace if blown - look for reason | |
operate. |
|
|
| first. |
| 2. | Contactor power circuit dead. | 2. | Check control transformer T2 |
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| and associated leads. |
| 3. | Broken power lead. | 3. | Check input voltage at contactor. |
| 4. | Wrong input voltage. | 4. | Check voltage against instruc- |
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|
|
| tions. |
| 5. | Open input contactor coil. | 5. | Replace coil. |
| 6. | POWER “I/O” switch (S1) not | 6. | Replace switch. |
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| closing. |
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Machine input contactor operates, | 1. | Circuit between #2 (C ) and #4 | 1. | Make sure trigger circuit is being |
but no output when trying to weld. |
| (D) is not being closed. |
| closed. |
| 2. | Electrode or work lead loose or | 2. | Repair connection. |
|
| broken. |
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|
| 3. | Open main transformer (T1) pri- | 3. | Repair |
|
| mary or secondary circuit. |
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|
| 4. | Defective Control PC Board. | 4. | Replace. See Procedure for |
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|
|
| Replacing PC Boards. |
| 5. | Primary or secondary ther- | 5. | Amber thermal protection light is |
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| mostats open. |
| on: Check for overheating; make |
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| sure fan is operating and there is |
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| no obstruction to free air flow. |
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| |
Machine has minimum output and | 1. Terminals 75, 76, or 77 grounded | 1. | Check 75, 76, or 77 for ground to | |
no control. |
| to positive output. |
| positive output circuit. Nearly |
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| zero ohms to ground indicates a |
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| grounded circuit. A value greater |
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| than a few thousand ohms is nor- |
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| mal. |
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| Board automatically reset within |
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| a few seconds after ground is |
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| cleared. |
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| |
Machine has high output and no | 1. Terminals 75, 76, or 77 grounded | 1. | Check 75, 76, or 77 for ground to | |
control. |
| to negative output. |
| negative output circuit. Nearly |
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| zero ohms to ground indicates a |
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| grounded circuit. A value greater |
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| than a few thousand ohms is nor- |
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| mal. |
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| Board automatically reset within |
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| a few seconds after ground is |
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| cleared. |
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– 23 –
