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| Chapter 12 Troubleshooting |
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Symptom |
| Measures |
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The needle stop position error oc- | • | Is the main shaft brake solenoid operating? |
curs. |
| If not, refer to the block diagram showing the cable connections and |
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| check to see if the connections from the brake solenoid to the power |
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| PCB and from connector P27 of the power PCB to connector P1 of the |
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| main PCB are proper. |
| • | Check the resistance value of the main shaft brake solenoid at the |
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| connector section of the solenoid. The normal resistance value is |
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| approximately 50Ω. |
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| If it is not normal, replace the solenoid with a new one. In this case, the |
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| power PCB in the control box may also be faulty. Replace it with a new |
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| one if it does not operate properly even after a new solenoid is installed. |
| • | Are there any problems with the main shaft mechanism? (i.e., The |
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| screw of the main shaft pulley is loose.) |
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The needle bar case lock error oc- | • | Is the INDEX motor rotating? |
curs. |
| If not, refer to the block diagram showing the cable connections and |
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| check to see if connection from the INDEX motor to the main PCB is |
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| proper. |
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| Check the resistance values of pins 1 and 2 and pins 3 and 4 at the |
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| connector section of the INDEX motor. The normal resistance value is |
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| approximately 4.4Ω. |
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| If it is not normal, replace the INDEX motor with a new one. Also |
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| replace the main PCB with a new one. |
| • | Manually turn the color change pulley. |
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| If it is abnormally heavy, adjust the color change mechanism and |
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| the needle cap case. |
| • | Start the machine after invalidating its initial setting and operate the |
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| head solenoid in solenoid test mode. |
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| If a certain head and the heads following it do not operate, refer to |
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| the block diagram showing the cable connections and check to see if |
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| connection of the head communication sign is proper. |
| • | Only head 1 does not operate. |
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| Check the communication line to head 1 and connection of the power |
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| harness for head 1. |
| • | Do the rotary switch settings of each head PCB correspond with the |
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| numbers of each head? |
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| If not, set them according to the head numbers. |
| • | Start the machine after invalidating its initial setting and enter the CASE |
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| test mode. Do figures on the panel change when the color change pulley |
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| is manually turned? |
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| If not, check to see if connection from the needle bar position sensor |
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| to connector P7 of the head PCB (1) is proper. |
| • | Replace the needle bar position sensor (potentiometer) with a new one. |
| • Replace the head PCB 1 with a new one. | |
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255 |
