TCL After-sales Case: After turning on the 2969A TV, both the horizontal and vertical synchronization were out of sync.
Analysis and Inspection: Based on the fault symptoms, the issue might be caused by the loss of the composite sync pulse signal or an abnormality in the sync separation circuit. In this model, the video full TV signal passes through the amplitude separation circuit composed of R233, C032, and C236. By utilizing the wide discharge effect of C232, the composite sync pulse signal is separated and then sent to the internal sync separation circuit via pin 41 of IC201 (LA7685). Upon measuring the waveforms at the output ends of R233 and capacitor C232 with an oscilloscope, they appeared normal. However, it was found that capacitor C236 had broken down and short-circuited.
Repair Method: After replacing the C236 capacitor with one of the same model, the fault was resolved.
Source of Article: http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3701157.