Over heating vertical ic

It is quite normal for the vertical ic to be hot. That is why it is mounted on a heatsink. My question is......are you saying you have intermittant horizontal lines at the top? Or occasionally after warm up you experience one horizontal line across the center? Your vertical IC may need to be resoldered. In this case you will have to decide to just resolder or solderwic the solder around the seven pins, clean with flux remover, wipe dry and reapply new solder. If you have (in most cases) White horizotal lines across the top, you need to replace the capacitors next to the ic. Correct polarization on the caps are neccessary. And dont forget to solder the ic as well. And any ground you may find along the way please resolder. Take two aspirns and call me in the morning!