Skyworth color TV 6D90 movement 29T61HT red light is not on the fault repair example - Appliances

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Maintenance Skyworth color TV 6D90 movement 29T61HT model machine red light is not turned on, measuring +B voltage about 40V, disconnect standby control circuit, voltage is 140V, measuring digital board 5V power supply is normal, use oscilloscope to measure memory SDA SCL voltage waveform There is no data exchange waveform during normal startup, and a single DC waveform of about 4.6V is presented.
Analysis is the failure of the digital board, including the relevant blocks of memory, CPU and data line "plug-in". .
First easy and then difficult, first disconnect the pre-view LM1269 SDA SCL connection chip resistor, boot high voltage, obviously LM1269 damage.
Summary: According to the conventional CPU "plug-in" integrated block damage caused by SDA SCL malfunction should be the CPU continuous data exchange, should be "busy" phenomenon, but this example has not been found.