The third picture really shows that this board needs a recap, as well as a thorough cleaning. The solder and solder pads around the caps and other components have some heavy corossion from years of capacitor leakage.
Given the state of the board (see below), I don't think it's a cap or goo issue, but then I may not know what it is I am looking for. Am I missing something obvious?
In the meantime, I'll do a search for troubleshooting the egret chip.
So far what I heard back from the curator was that the vast, vast majority of what they have is there in physical storage and not scanned. I am awaiting to hear how one accesses the main documents in person, but with COVID it appears the campus will be closed for a long time with no chance of looking things up. However, the possibility exists for one of our CA friends here to be able to peruse them someday and perhaps obtain schematics for everyone.