My old company had experienced a loss of all generators on one of their B-727s about 30 years ago.
Turned out that the airplane's Constant Speed Drives coupled to the generators were mistakenly ground serviced with Skydrol by a mechanic fresh out of school . . . . All 3 CSDs had seized about 30 minutes into the flight, but luckily this occurred during day VFR.
Perhaps history repeating itself?