HOW TO TROUBLESHOOT CHINESE TV KIT USING _ LA-76931 AS MCU+DECODER

     If you have remote control [DGT-5AM3], it has a hidden key (a hole on it) by which you can activate the service mode by it.  To Exit from service mode too, you can use this hidden key.


SERVICE FLOW CHART


POWER SUPPLY
Check input voltage => Check voltage of C910 anode => Check pin number 3 of N901 => Check V910 => Check output voltage of T901 secondary coil => Check voltage of N904, N905 Pin-3 [5V] and N903 pin-3[9v] => Check voltage of N103 Pin 8,31,32,35,36,43,55 [5V], and pin 11,19 [8v] => check voltage of N602 pin 8 [+5V].


AUDIO CIRCUIT


Check supply to audio power amp circuit => Check input audio signal.


HORIZONTAL CIRCUIT


Check voltage of T402-pin 3 [110V] => Check voltage of N103 pin-19[+9V] => Check frequency at V401 base => Check wave form of V402-collector => Cehck output voltage of T402 coil => Check wave form of T402 pin-8.


VERTICAL CIRCUIT


Check voltage of N440 pin-2[+25V] and pin-7[+9V] => check voltage of N103 pin-19[+9V] => check waveform of N103 pin-17 => check waveform of N440 pin-1 => check waveform of N440 pin-5.


MCU CIRCUIT


Check voltage of N103 pin-31,32(+5V) => Check waveform of N103 pin-33.