Television fault diagnosis, repair and tipsFault check
for rapid, accurate fault inspection of TV receiver, must understand the system check order and flexibility in the use of measuring instruments (such as multimeters, voltmeters, Oscilloscopes, etc), of particular importance is the use of a multimeter. Fault check to high readiness efficiency, usually in the following order: careful attention to image and sound changes, such as adjusting knob, confirm very well expressed through images and sound failure symptoms. Judging fault circuits or components. According to the judgment of the program, with the examination of measurement instruments, tracks the location of faults.
replacing a failed component, verify that it is working properly, and finally must verify that the reference of the knob is normal.
1, by adjusting the knob to confirm the failure symptoms and determine the steps is to adjust the various fault circuit check the knob, carefully observe symptoms such as bad symptoms observed, tend to fault location of error will be generated. Each knob to determine the relevant circuit:
(1) AGC adjustment knob: because the AGC voltage is added to the high frequency tuner and image in the circuit, so able to inspect their bad situation.
(2) channel switch and frequency tuning knob: can be used to check for high frequency amplifier and local oscillator high frequency tuner part of the circuit and the circuit (using a multivibrator appliances). Secondly, through the Rotary frequency fine tuning knob can judge image-poor condition of intermediate frequency amplifier.
(3) brightness control knob: "to check the power circuit, the picture tube circuit, high voltage power supply circuit and output circuit.
(4) contrast adjustment knob: to check the video amplifier circuit.
(5) field hold control knob: to check the electric field oscillation and synchronization separation circuit for integral circuits.
(6) range adjustment knob: to check the electric field oscillation, the field excitation and vertical output circuit. The knobs are usually received electric field oscillation, to change the resulting sawtooth wave amplitude. When the knob and rotate, and its linear sawtooth wave will go bad.
(7) with synchronous adjustment knob: to check the AFC electrical circuit, oscillation and horizontal output circuit.
(8) linear regulator: hands to check the field excitation and vertical output circuit. Adjust the knobs can be corrected through the sawtooth current waveforms of the deflection yoke.
(9) volume knob: used to check all circuit to reproduce sound signals.
(10) knob: for TV, there gathered adjustment, power switch knob. In addition, when the image does not appear, check for sound, sound then the fault is in the image of the circuit or circuit if no sound then the fault is located in the tuner. For color television receivers, using the channel selector switch check "do not appear accurate coloring" fault. Due to the different fault symptoms correspond to each circuit, you must understand the working principles and functions of the to determine the fault circuit.
even if the fault circuit fault location range, this will not work. Must also further the circuit down to the before and after of a transistor or IC, then use a multimeter, tools, and lead wire, check individual test points