I am always somewhat bemused that not everybody loves working on machines and as for the psychologists and medical types, well that is really just witchcraft to me. Why anybody would choose to spend their days trying to fix such an unwieldy machine as the human body is utterly beyond me, although I am grateful that some choose this path. If the complication and absurdities of the human machine are not enough, I mean who would put a nerve in the porcelain that they intend to use as a crushing machine, there is the interface my god it makes Apple look sensible!
In order to understand what is happening within the machine that is the human body a lot of the diagnosis is performed by interfacing directly with the owner. There are no sensible fault codes, no logs to download, just a blithering idiot telling you “it’s like a sharp pain on the inside”, hopeless. And that is just the medical side, if we turn to those who work on the CPU then the interface is even more ethereal. There are no simple test points you have to diagnose the problem by picking trends out of huge data dumps and even these are not given freely. To extract the data dumps you need to keep applying random passwords until you hit lucky and pretty much the entire memory is dumped, in no order, in a stream of nonsensical drivel. The output isn’t produced in .csv format or anything that can be usefully interrogated later oh no it is sent straight to the speaker with no back up. Who would code a CPU like that? The closest equivalent is the infamous windows blue screen of death but even that stays fixed on the display so you can actually read it in your own time.
Now you may wonder what got me to thinking this, I shall share the reason but please don’t tell anybody. I tried another of these dumbass questionnaire things and it confirmed, as they all seem to, that I am a psychopath, you will appreciate now why I am telling you in confidence. There are various reasons why I am considered to be great psychopath material but in this case it was my preference for machines over people and I think that unfair. Preferring machines is simple logic and I am an Engineer of course.
This weekend I spent some time playing with a failed vending machine, it takes credit but does not vend, there is no support material available. To start with I identified the relay that operates when the vend is requested, since it was a micro relay it had to be controlling some larger relay because the motors are 240v. Finding the hidden box that contained the transistors switching the motor feeds I discovered that there was only one set and, since service mode worked the fault did not lay there. The next area to check was the relays on the main board, since there are three, but to test these involved soldering test wires to the coils and powering them up on the bench, all worked ok. Having traced most of the circuit on the PCB I now know that there is only one motor feed and in vend mode it is switched by a light beam detecting the vend. I have located the correct connector and added test wires to it so that I can replace the board and check the inputs in situ which is the next task.
Now some of you read the previous paragraph and glazed over, my apologies to you, some of you are questioning the order of my approach and just why those relays needed testing and you my friends are apparently psychopaths, it’s ok I wont tell anybody. How anybody cannot find pleasure in reverse engineering and diagnosis is beyond me, unlike a human all of the inputs are logical, well presented and unambiguous you simply need to understand how the designer chose to use or derive them. Now if that makes us, see the way I included you there, psychopaths then so be it but a quick check of history will tell you that more doctors maliciously and intentionally kill than Engineers, just saying.