Maintenance tips: For faults involving large-scale damaged components, the replaced components must be tested, and high-quality components are recommended to prevent secondary faults.
For example, in Konka TVs, the power circuit thick film block and line output tube often burn out upon startup.
Article source: Beijing Konka TV Repair Center http://blog.163.com/konka_dianshi/.
Analysis and Maintenance: Based on the fault symptoms, the voltage regulator circuit of the set has an excessively high voltage, causing the line scanning circuit to generate an overvoltage that breaks down Q421. When the voltage regulator circuit loses control, pins 8 and 9 of the thick film block STR-S6309 will also lose control, resulting in a loss of control in the secondary output voltage.
After the above analysis, it is necessary to focus on checking components such as IC3, IC2, Q90J, R913, R914, R915, and ZD902. Upon inspection, it was found that IC2 had internal open circuits, and R911, R930, and C913 were all damaged.
Repair method: Replace the aforementioned damaged components to eliminate the fault - Beijing Konka TV Repair Center.