Quoted from Scmitchell:Latest update. The transistor Q 4 actually has a bit of the black (Heat sync?) missing. Did this possibly get so hot it broke off? I am planning on ordering a new TIP and the driver. Would these make the pops completely inoperable?
If the transistor is cracked it's busted. Anything connected to it is not going to work correctly. That is the classic way that those TIP transistors break - pieces will blow off, or you'll see a solder-like ball on the end. The heat sink part of a TIP transistor is the metal tab. The black stuff is the transistor body itself.
