oneTesla

Hello. Help me solve the problem, please. I have two coils One tesla, they was constructed and successfully worked for a while. One was broken, presumably after overload, when it had played not a standard tune with high power. Second broke down, surprisingly, immediately after I had inserted the IEC cable. Transistors and diode bridge were destroyed. Instead of the standard transistors I had established counterparts, and the coil have been working for four tests. But, with the correct connection sequence, and checking the low-voltage circle, after the IEC cable had been inserted immediately occurred cotton, transistors were destroyed again. Please, tell me, what could be the reason of the damage?

I beg your pardon for my English)