TIP102's are the hot ticket these days.

I had this argument with a well know repair guy once about why Bally selected the Darlington that they did. If fused correctly the transistor had an interesting feature. They would crack and go open in most cases upon failure. That came from Bally Distributor Service School in 1982. Williams was similar with it's "specially selected" TIP122. I know many of you have seen that term.

What was so good about that? Didn't blow holes in the circuit board very often, even when slightly over fused. Of course not everything is perfect in this world and sometimes that little "not-designed" plus did not happen. But many times in the field I replaced those original Darlingtons and there was no board damage.

A TIP102 will stay on longer because of it's current carrying ability so if it is over fused things may get ugly. I've repaired more of those damaged boards since everyone started using TIP102's. Double check your fusing.

Just a little history for what it's worth.