Beijing Skyworth TV Repair Center -- Editing and Organizing Materials.
Analysis and Inspection: When switching channels, using a multimeter to measure the voltage at pin 22 (video output end) of the image intermediate frequency circuit TDA2549 shows significant changes, indicating that TDA2549 is working properly. The fault lies in the Y/C separation switching and decoding circuit. When switching channels, measuring the voltage at the negative end of input coupling capacitor C288 (pin 33) of the color decoding circuit TA8659 shows no change, while the voltages at all pins of the Y signal switching circuit IC2004 (TEA2014) are normal. The voltage at pin 3 changes when switching channels, but the voltage at pin 6 (output end) does not change when switching channels. It is found that TEA2014 is damaged.
For the Skyworth CTV-8298WF TV model, the blue screen and character display are normal, but there is no picture or sound.
Solution: After replacing the TEA2014, the fault is resolved.