Color TV Scanning Circuit Fault Diagnosis and Maintenance.doc

Color TV Scanning Circuit Fault Diagnosis and Maintenance Abstract: The color TV in use for some time, there will be a variety of failures, in which the failure rate of sweep circuit is relatively high. Therefore, color TV’s fault repair often involves scanning circuit. In this paper, the phenomenon of the scan circuit failure analysis to determine the fault position in the end color TV is not in the scanning circuit, if it is in the scanning circuit, and specific location of the scan circuit which? How to overhaul a variety of failures? Maintenance should pay attention to issues. Keywords:: color TV scanning circuit troubleshooting TV scanning system, including tubes, tube power supply circuit, line scanning circuit, field scanning circuits and synchronous circuits. Its main role is to make a normal CRT screen to form the grating. One-line scanning circuit, field scanning circuit and the synchronization circuit known as the scanning circuit, their main role is to control the electron beam scanning movement, the screen on the formation of a normal grating. 1, scan the main technical requirements of the circuit (A) line scan circuit of the main technical requirements 1, line scanning circuit should enable the line deflection coil produced good linearity, amplitude sufficient frequency stability of the line frequency sawtooth current. 2, providing tube electrodes with high pressure and medium pressure needed. In the high-voltage DC power supply for large-screen TVs, and some also can provide high-frequency head, public access and other needs of low-voltage circuit. 3, must be horizontal sync pulse signal synchronization, thereby maintaining its scanning frequency of 15625Hz, process time is 51 ~ 52μ s, inverse process time for 12 ~ 13μ s. 4, must provide the local line blanking pulse signal, eliminating bright-line flyback lines. 5, must provide the necessary comparison of AFC circuit sawtooth signal to AFC circuit can output control voltage. When the row s