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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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| E. Machine does not have | 1. | Input fuse blown. Machine is | 1. | Replace fuse or repair input line. | |
| maximum output (67 to 71 volts). |
| single phased. |
| Check reason for fault. | |
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| 2. | One phase of main transformer | 2. | Repair. |
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| windings open. |
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| 3. | Defective power bridge. | 3. | Check bridge. See |
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| Troubleshooting Procedures – |
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| Checking Snubber Circuit and |
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| Power Rectifier Bridge Assembly. |
| F. Machine comes on but soon trips | 1. Improper ventilation. | 1. | Make sure all case openings are | ||
| off while under load and High |
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| free for proper circulation of air. | |
| Temperature Warning Light |
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| glows. (Choke or Secondary | 2. Loaded beyond rating. | 2. | Operate at rated current and | ||
| thermostat tripped) |
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| duty cycle. | |
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| 3. Fan inoperative. | 3. | Check leads, choke and sec- | |
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| ondary thermostat and motor |
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| bearings. Fan can be tested on |
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| 115 volt line. Check thermal fan |
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| thermostat. |
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| 4. | Shorted diode or SCR in power | 4. | Refer to Power Hybrid Bridge |
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| rectifier bridge. |
| Checking Procedure. See |
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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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| 5. Defective thermal fan thermostat | 5. Replace | ||
| G.Machine comes on but reduces | 1. | Excessive load causing the over- | 1. | Reduce load. | |
| to low output under load and |
| load protection on control board |
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| remains there until the load is |
| to operate. |
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| broken and arc |
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| Fault Protection Operation | 2. | Machine output shorted causing | 2. | Turn machine off and remove | |
| Section. |
| overload protection on control |
| short. | |
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| board to operate. |
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| 3. | Control circuit defective. | 3. | Replace per PC board replace- |
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| ment. See Troubleshooting |
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| Procedures – Replacing PC |
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| Boards. |
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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