How to detect the fault of CRT display line output circuit

The line output circuit is an important circuit in the display circuit. In the event of a failure, the monitor will not function properly. In actual use, the output circuit of the monitor often appears short-circuit fault, Open-circuit fault and contact bad fault. The short-circuit fault will make the line tube set electrode on the ground resistance is very small, causing the monitor to boot without grating, power LED is not bright or flashing, accompanied by squeak or clatter sound.

And the Open-circuit fault is mainly the S-corrected inductance coil, which is caused by the large volume and large heat-removing components. Usually shown as vertical bright line or without grating, the reverse capacitance of the pipeline most of the breakdown damage.

When there is a contact failure, the monitor becomes normal and abnormal. is generally caused by the heat of the components off welding.

In general, the output circuit of the next sweep transformer damage, damping pipe and the reverse capacitance of the majority of bad. There are but not many damage to the deflection yoke. In practice, the process of the reverse capacitance welding is more common. When the display line output circuit failure, you can follow the following methods for maintenance.

(1) When the failure of the machine, do not boot case under the circumstances of the first to see the response of the computer. Generally speaking, there are three kinds of situations. One is the power LED is not lit, the second case is the power indicator light is normal; the third situation is the power indicator light to turn off alternately, accompanied by squeaking. In addition, note that there is no abnormal sound, smoke and so on.

(2) After dismantling the machine, the general is to check the line C-pole to ground resistance, +b1 resistance. If normal, you can add electric test machine. Otherwise, the ground short circuit fault must be eliminated first.

(3) The ground resistance can be added to the normal electrical test machine. If the ground resistance is not normal then look for short-circuit fault components.

(4) When the measured resistance is found to be very small, the breakdown of short-circuit components. First, to observe the appearance of abnormal components, before the replacement, and then retest of the ground resistance.

(5) If it is not normal, the next need to check the section, one by one, if necessary to remove the measurement.

(6) then pull the deflection yoke plug, the acceleration pole knob to the left to the end (the acceleration voltage to the minimum, to prevent the absence of deflection current generated bright spot burns picture tube), retest. If the normal description of the line deflection is bad, otherwise it will be back to sweep transformer bad.