Couple of interesting videos from a fellow in Australia. Source is this thread on Ben's Whirled, post #42-43. I think this is a late M117 EZL, not M119, but the principles should be similar and both drive distributor ignition systems. From the description for the video below:
"It is of my unprofessional opinion that the coil switching transistor [EZL] failure is a symptom of the failure and not the root cause.
The affected vehicle had a poorly maintained ignition system. It is of my opinion the damage to this custom silicon in the EZL was caused by excessive inductive spiking from the ignition coil as a result of the poor condition secondary (HV) components. With this dead short the coil switching transistor is held ON permanently and as such its fly lead to ground simply vaporised under the current available from the car battery. This die only runs on extremely low current 5VDC and the damage can be explained no other way."
This BW thread had some interesting photos inside an M117 EZL.
And, this thread has photos inside an M119 / 500E EZL.
What really happens to an EZL with a poorly maintained ignition system?