Something has been blown

César EA3IAV

Yesterday I installed everything and it worked fine...
Today I put everything in the box and decided to use the case as heatsink. I put insulator and thermal silicone. Ok i turned it on and there has been a little explosion and smoke in the area of the transistors. I don’t see anything blown... 
maybe i blew the transitors? How can I check? I did tested that there was no continuity between the metal thing of the transistor and the screw! 
Hell i hate this!

now after removing the transistors from the case it turns on normally 

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