Quote:
Originally Posted by peter_sol
I doubt anyone is "having a laugh".
They just don't know.
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I think this is true a lot of the time.
It is amazing what non technical people can believe about technical people and the challenges they face in their work. I remember a fellow once remarking that it must be very easy to fix VCR's and TV's because to do it you just "follow the wires and see what is wrong". Or another customer upset about a hundred dollars of time spent on a job, to find a shorted 50 cent ceramic capacitor.
Obviously for a repair technician to be effective they have to understand the theory of the circuit they are working on and how the sub circuits are implemented, so as to be able to home in on a fault quickly with the knowledge of where the likely sub circuit responsible for the signs of the fault resides.
Still even with this knowledge & experience there are situations where the logic can fly out the window and make even the most experienced technician struggle. One classic is new sub circuits that get created by leakage pathways on a pcb, caused by leaked electrolyte or tin whisker conduction. The faults can seem bizarre or even impossible and not relate to the original circuit architecture.
Another is in cmos logic where an output of an IC goes open leaving some gate inputs floating, they discharge immediately when the scope probe is attached making it look like a logic 0 when some of the time it is not. And of course there would be numerous other examples.
But the layperson expects the technician to be on top of it 100% of the time and are baffled when some equipment takes a while, or is costly to repair.