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Experience of Fault Diagnosis of CRT TV Black Screen

Time£º2017-04-13 08:09:14  Source£ºNetwork  Author£ºUnknown  Clicks£º11948

CRT TV black screen troubleshooting experience Summary:RCWservice manual download site
 Repair a few years of TCL TV, black screen failure is one of the most troublesome one of our troubles, especially the Philips movement, due to some special circuit to our bolt repair a lot of trouble. We are here on our daily encounter black screen fault to do a simple analysis. There are many reasons for the failure of the black screen, first of all to determine whether there is no sound, if there is a description of the power supply is basically normal, and then to determine the line did not start, so that we can reduce the scope of the fault, we are here only Discuss the black screen failure after the start of the line.RCWservice manual download site
 Causing the line after the black screen failure causes the following main points:RCWservice manual download site
 First, the filament does not shine; if the filament does not light, we will check the filament power supply path whether there is open circuit failure (and our filament power supply row plug welding failure rate is higher), filament is open or short circuit.RCWservice manual download site
 Second: the accelerating voltage is not normal; our common acceleration voltage is not normal caused by the black screen failure mostly caused by improper adjustment of the accelerator, which is different from the movement of the Philips movement is a feature, Toshiba movement and Sanyo movement If the acceleration is not properly adjusted will only lead to abnormal brightness is not normal; followed by the acceleration of short circuit, which is generally CPT internal short pole, we just quickly remove the tail plate and then test whether the acceleration voltage can return to normal value can be determined Whether the CPT is damaged;RCWservice manual download site
 Third: dark current feedback is normal; dark current feedback circuit is to detect the cathode cathode current continuous correction of the cut-off current, improve image quality, and can protect the CPT, but it increased our black screen fault repair, we can By detecting the dark current feedback to detect whether the pin voltage is normal to determine whether this part of the circuit problems (ie BLKIN input feet) normal operating voltage of 7.5V. The dark current detection circuit includes a CPU circuit, a decoding chip, a viewing circuit, a CRT circuit,RCWservice manual download site