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故障现象1:开机后打印头小车能回到左边界位置,但来回动两下后就停止了,并发出报警。故障分析及维修:小车能归位就表明主控制电路、走车控制和驱动电路没有问题。应从打印头温控电路去找故障。因为当打印头温度升到100℃时,打印头小车会自动回到左边风扇附近降温。检查发现打印头温升保护电路中的 IC14B(LM2903)微分比较器的输出端脚1和脚7为低电平,使打印机进入保护状态,说明IC14B已损坏。更换IC14B后故障排除。故障现象2 打印机开机后,指示灯不亮,打印头小车不动。故障分析及维修:开机后指示灯不亮,说明电源有故障。LQ1500打印机的电源开关采用桥式整流、滤
Symptom 1: After the boot print head car can return to the position of the left border, but stopped back and forth twice, and issued a warning. Failure Analysis and Maintenance: Car can be homing that the main control circuit, car control and drive circuit is no problem. From the print head temperature control circuit to find fault. Because when the print head temperature rose to 100 ℃, the print head car will automatically return to the left side of the fan cooling. The IC14B (LM2903) in the temperature rise protection circuit of the printhead was found to be low by pin 1 and pin 7 of the differential comparator, putting the printer in a protected state, indicating that the IC14B was damaged. After replacing IC14B troubleshooting. Symptom 2 printer boot, the light does not shine, the print head car does not move. Failure Analysis and Maintenance: The indicator does not light after power on, indicating a power failure. LQ1500 printer’s power switch with bridge rectifier, filter