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Trouble removal of EPSON LQ-670K printer 3

来源: 作者:Stand originally 时间:2008-12-22 Tag: 点击:

Breakdown phenomenon one: After adding paper, be short of paper lantern to still shine, do not print

Analysis and eliminate: The check paper circuit of this printer has 3 sensor, around does reed sensor twice to be used at detecting to print paper to send. Once paper touchs the reed of sensor, make the contact movement of sensor, printer starts the program that take paper, send exact position automatically paper, to print ready-made. The process is here medium, whether did the paper that print reach corresponding place, be in charge of detecting by sensor of another photoelectricity type. When paper reachs the designated position, on Control Panel be short of paper lantern to go out.

From the breakdown phenomenon analysis of above, estimation is photoelectricity sensor has trouble. The author gave photoelectricity according to objective picture sensor and advocate dominate the partial circuit between circuit board, if pursue. From the analysis in the graph, glow diode is received the 1 foot at plug-in unit CN5 and between 3 feet, resistor R6 is strung together receive at + 5V in the power supply loop to glow diode, have the effect of step-down and current limliting. Below normal circumstance, when having paper, because photosensitive canal does not receive the light that comes back from reflex of the paper that print, be in off-state, 4 feet output low n; When having paper, photosensitive canal guides, 4 feet output the tall n that is close to + 5V.

Below online condition, measure 4 feet voltage with avometer, no matter have paper or without paper, 4 feet voltage all is low n; And when using lamplight irradiation, 4 feet voltage turns into tall n, showing photosensitive tube is good. Measure 1 foot voltage again, for + 5V, abnormal (normal when, the voltage drop of two end should be glow diode + 2V is controlled) . Check the joint of probe and flexible cable, connection case is good. From this, judgement glow is in charge of already open circuit. Change new photoelectricity to detect probe, trouble removal.

Breakdown phenomenon 2: When printer is used, stop suddenly machine, pass opportunity of the reopen after machine, without any reaction, power source light is not bright also.

Analysis and eliminate: Open printer housing, pull out all join head, tear open next printer crust and screen cover, make circuit board is shown. Check power source circuit, discover fuse is in good condition, other part also did not discover the trace of apparent burn down. Switch on the mobile phone to detect with avometer rectification outputs end, have output of + 300V voltage, normal. Because do the circuit structure of place of the other in circuit of not clear power source and each,output the definition of end, because this cannot undertake temporarily,went down.

With the background of experience in maintaining practice for years, the decision is checked from laden end. Above all, arrive down join advocate accuse board the outlet that go up undertakes checking, make clear the function of every outlet. Among them CN6, CN7 is the drive line that needle and brief shot grow in the head that print respectively, CN8 is line of drive of paper electric machinery, CN9 is line of drive of word car electric machinery, other outlet all connects contact for sensor.

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