PCB News - How would you diagnose a problem with the circuit board

How would you diagnose a problem with the circuit board

Have you ever had this kind of experience: When you finally figure out the cause of a certain technical problem on the circuit board, you can't help but jump up and laugh and shout?

In the untestable era, the company's executives once participated in a job interview. One of his interview questions was: "When a printed circuit board has a problem, how would you diagnose it?"

As you can see, this is a very open question, so I immediately answered: "I will guess first;" Then the chief examiner asked me not to accidentally continue to explain, and of course I was happy to continue. I explained that there are different ways to solve problems like circuit board failures(here we assume that you don’t have a circuit board tester equipped with specific test procedures). In fact, the first thing I will do is to quickly visually inspect the circuit. Board, look for obvious clues such as loose jumpers (missing), burn marks around resistors, capacitor explosions, stress residual solder joints... etc.

It sounds a bit stupid, but time and time again, you will be lucky to find some obvious clues. After the first visual inspection, one option is to carefully inspect all possible failure mechanisms, inspect components, test wiring, and observe individual signals until the failure point is isolated. The problem with this strategy is that the process is both boring and time-consuming.

Another alternative, which I personally recommend, is to observe how system failures appear in the external world, and then start WAG (wild-ass guess) random guessing based on your observations.

The reason why this method is not as stupid as it sounds is that you are using your wealth of experience to quickly move towards the problematic area; if you are right and find the problem correctly, you can save yourself A lot of time and energy; if you guess wrong, you will not waste too much time or energy, and at least one possible problem has been ruled out.

But at some stage, you may need to check some more WAG results, and then you return to the careful, slow and steady progress, and energy-consuming analysis mode.

What? Then? Of course I passed the interview...what silly question to ask!

However, none of the above is actually the point; I think of those because I just watched a series of interesting "On-call" (On-call) on the website "The Register" (Editor's note: a British technology news and review website). Call) article, the slogan of this series is "bite those hands that feed IT". It is a regular column every Friday, where readers of IT technicians share the strange tasks they have performed at strange times and strange places.

I have read two very interesting stories so far. The first is about a computer that restarts itself whenever the owner flushes the toilet; the second is that the network of a certain theater is every time the audience arrives and prepares to receive When the ticket enters the venue, the line is hung up.

Such technical problems may often cause engineers to stay up late to solve them, but if you find the reason, it really makes people jump up and cheer, shout and laugh...Have you ever encountered that kind of experience as an engineer? Welcome to share with us!

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