Re: Percussive maintenance
Though I appreciate the story I would just mention that faced with mysteriously nonfunctional equipment, my first step has always been to pull out a multimeter and check all the power rails.
This was after a piece of equipment was redesigned, and the DC/DC converters were moved from a corner of the instrument to the backplane, the logic being that they were then cooled by the large fans that blew air across the circuit boards from front to back.
The PSUs ran cold but the cpu kept rebooting itself.
The simple reason was that the backplane traces were inadequate and the voltage at the cpu was about 4 volts. Every time the offboard bus switched (this is TTL), the surge risked dropping the volts till the oscillator dropped out.
The result was an ugly mess behind the backplane of big thick wires running from one end to the other of each power trace, soldered at every circuit board plug.