I am repairing one inverter. The power section consist of switching power supply controller TDA 4601. The problem is that at pin 2 the zero crossing detection the capacitor of 22pF is connceted b/w pin 2 and pin 3. The power supply is only starting when i touch any metallic thing at pin 2 for a moment and then removed, it continues to work, otherwise not. I have already change differnet value of capacitors but the problem is still there. The Switching transistor is BUV 48A. If any one can help me, i will be very thankful of him.