My apologies to the OP for derailing your thread, but I've seen this same misinformation perpetuated over and over, so I wanted to present information that isn't from a 12 year old thread with loads of conjecture. And yeah, I disliked opt2not's posts after the fact, I've gone ahead and removed it.
I've worked on a number of 2930/2931 chassis over the last 10 years, and while the potting compound was present on many of them, the faults were not always with components that had the compound on them. It's long been known that it's not conductive, and it doesn't come from the flyback, so saying that it causes the flyback to fail is pretty wild.
Now, isn't it just as likely that these chassis experience high failure rates because of their design and delicate components? And the potting compound leaks due to the high amount of hours/high heat/bad batch of epoxy? So, invariably, you're going to see the potting mixture leak at some point or another given the general age and environment.
Recall these are the same chassis that folks have had kill tubes, so they definitely seem to have a design issue. I've personally not had it happen, but I believe it to be true. I've also personally ran these chassis without cleaning up the epoxy and had no issues.
At any rate, correlation does not imply causation.
For those that want to know what some of the features potting compounds provide in electronics.
