Basic Problem Solving
TYPE OF | WHAT TO CHECK | WHAT TO DO | |
PROBLEM | If check is OK, go to next check | When check is not OK, refer to this column | |
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Electrical | 4. Check motor brushes for the following: | 4. Refer to page 21. | |
(continued) | a. Loose terminal screws. |
| a. Tighten. |
| b. Broken or misaligned brush springs. |
| b. Replace broken spring and/or align |
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| spring with brush |
| c. Brushes binding in holders. |
| c. Clean brush holders. Remove carbon |
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| with small cleaning brush. Align brush |
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| leads with slot in brush holder to as- |
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| sure free vertical brush movement. |
| d. Broken leads. |
| d. Replace brushes |
| e. Worn brushes. |
| e. Replace brushes if less than 0.5 in. |
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| (12.5 mm) long. |
| f. Brush leads snagged on spring clip. |
| f. Correctly route the wires. |
| NOTE: The brushes do not wear at same |
| See page 21. |
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| rate on both sides of motor. Check both |
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| brushes. |
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| 5. Check motor armature commutator for burn spots, | 5. Remove motor and have motor shop | |
| gouges and extreme roughness. Remove motor |
| resurface commutator if possible. |
| cover and brush inspection plates to check. See |
| See page 23. |
| page 21. |
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| 6. Check motor armature for shorts using armature | 6. | Replace motor. See page 23. |
| tester (growler) or perform motor test. |
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| See page 20. |
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| 7. Check leads from pressure transducer and motor | 7. Replace loose terminals; crimp to leads. | |
| to motor control board (22a) to be sure they are |
| Be sure male terminal blades are straight |
| securely fastened and properly mated. |
| and firmly connected to mating part. |
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| 8. Check motor control board (22a) by performing | 8. | Replace board. See page 24. |
| motor control board diagnostics on page 24. If |
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| diagnostics indicate, substitute with a good board. |
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| CAUTION: Do not perform this check until motor |
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| armature is determined to be good. A bad motor |
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| armature can burn out a good board. |
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| 9. Check power supply cord (30). Disconnect black | 9. Replace power supply cord. | |
| and white power cord terminals; connect volt |
| See page 25. |
| meter to these leads. Plug in sprayer. Meter should |
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| read |
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10.Check ON/OFF switch (80). Disconnect black wire (96) between motor control board (22a) and switch and connect volt meter between exposed terminal switch and power cord’s white wire. Plug in sprayer and turn ON. Meter should read
10. Replace ON/OFF switch. See page 25.
| 11. Check motor thermal cutout switch. Connect ohm- | 11. Allow motor to cool. Correct cause of |
| meter between motor’s red leads. Meter should | overheating. If switch remains open after |
| read 1 ohm maximum. | motor cools, replace motor. |
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| 12. Check the transducer (67) by replacing it with a | 12. Replace pressure transducer. |
| new one. | See page 28. |
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| 13. Check pressure adjustment potentiometer (77) by | 13. Replace potentiometer. |
| replacing it with a new one. |
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