Eeyore schrieb:

Since when did one side of a complementary pair fail w/o taking the other one
out btw ?

Yes, the most commen failure is a shorted transistor, but there a
several cases in which one of the complementary parts is not driven
(driver transistor w/o supply) the emitter path is broken (emitter
resistor blown) or the overcurrent protection has failures...

In these cases only one side of the power stage drives current to the
output.

Some amps have additional fuses only for the last power stage, so it
could happen that only one half of the stage is working in case of a
blown fuse...

- Udo