According to the symptom, preliminarily concluded that field scanning circuit anomaly. Measuring farm output block N301 (TDA8359J) the PIN voltage, find {3} pin voltage is 0V, normally 15V. Further examination revealed a current-limiting resistor R516 (0. 33 ω/1W) open and discoloration, while N301{3} feet breakdown short circuit to ground. After replacing R516, N301 commissioning, troubleshooting.