before all the B guys get too smug, ask yourselves what would happen in your machine if critical displays and systems continually were shuttled between busses by an intermittent electrical problem?
In 1991 BA received delivery of B737-400s fitted with the new VSCF, instead of IDGs. (Variable speed constant frequency).
Anyway a two week old example arrived here with the following defects.
Galley power repeatedly switched itself off
Lighting system flickering, cabin and cockpit.
Flight Recorder OFF light intermittent ON.
EFIS and FMC dumped all info and L Nav and A/Thrott disconnected, Track disappeared from EFIS
Pressurisation problem felt but no warnings
Then nbr 1 eng gen bus off light on, and all back to normal.
BA soldiered on with the VSCF for many years, but finally gave up and converted to IDGs.