No. There is no switch to issue a May Day. All we have is a radio, which may have been disabled with the transponder. There is also a transponder code for emergency, but again, n avionics fire could easily have taken both those out.
Note to future commercial aircraft designers. If a situation occurs where a pilot cannot make a distress call, have doomsday switch on a panel on it's own dedicated circuit with it's own aux power supply that when hit sends a distress signal. Would have thought that would have been available.