Restoring a Diamond Lady and just swapped out these poor bastages on the transistor driver boards. Apparently some of the coils locked on and the previous owner let it go until they fried.

The boards were toasty and blackened behind the transistors. Luckily, no traces were burnt thru and continuity checked out for all the connections. That one transistor had to be glowing hot before it finally died.

20150202_215409.jpg