bearfoil:
Keep in mind that N3 continued past Burst, and fed a fire. The EEC may have had problems similar to Number One. Remember Number One was impossible to shut down, and with sound internals, (until swallowing canal mud), it ran on two hours.
A commanded engine shutdown is only possible through direct connections from the engine master switch to the HP fuel shutoff valve or from the fire push button to the HP and LP fuel shutoff valves. The EEC's authority to close the HP shutoff valve is limited to a few specific cases (e.g., aborted start sequence or certain protections). The fact that engine 1 could not be shut down indicates defective wiring between the switches and these valves but does not imply that the
EEC had any problems in controlling its engine as designed.
Independently of this, I still wonder why exactly engines 1 and 4 went into degraded mode, i.e., what led to the loss of internal and external(?) data (certain pressure and temperature measurements were mentioned in an older post) that is supposed to cause this degredation.
The EEC has two channels, each one an independent system that is dormant when the other operates. At ignition, the EEC determines randomly which channel to activate, and which to isolate.
Not randomly. Under normal conditions the active channel is changed with each engine start.