My home wired/wireless router has worked faithfully for the past few years: no crashes, no headaches, and coming back up quickly and smoothly from the occasional AC power outages. So I didn't suspect it when my Internet access—as seen by my PC and network—started flickering off and on for a few seconds. Was it strong local interference? Was it the PC doing strange things? Or maybe there was an intermittent connection inside the router? I wasn't sure.
Luckily, this router has a set of LEDs indicating power on, data transfers, and basic connectivity. I noticed that all the LEDs went off for a few seconds, and then came back on. I kept an eye on them, and sure enough, the LEDs went off in sync with my access problems.
Long story short: the DC-power connector to the router, coming from the AC/DC converter (aka "wall wart") had gone intermittent. A little more investigation revealed that it had problem been on the edge, literally and figuratively, for the past years, but now those routine, tiny household vibrations were pushing it "over the edge" randomly, for a few seconds.
Once I identified the problem, the solution was easy: I hot-glued a few cable clamps to the router top, then strapped the DC-supply cable to those clamps using standard nylon ties. Result: I immobilized the cable and connector in a "good" position.
But from a design standpoint, I wonder if the engineers or marketers of this otherwise excellent product realize how they have caused me headaches, and likely caused unnecessary product returns and warranty problems. All the Ethernet cables connecting to this box use the standard "RJ" connectors, and so have that little locking snap-release which holds them in place. Sure, it's not a ruggedized, mil-spec connector, but it keeps the cable in place well-enough for this benign application. In contrast, the much simpler DC- supply link uses a standard, cheap mini-plug, which we all know is only so-so reliable, and is especially sensitive to sideways (radial) loading, which it will certainly get from the weight of its wires.
I can feel the dilemma the designers faced. To simplify sourcing of the AC/DC wall wart, they went with the ubiquitous, inexpensive unit and its mini-plug connector, rather than use a non-standard, snap-in, positive-locking connector. Maybe they realized the potential for problems, but faced cost, availability, time-to-market, or other pressures to "check" this item off their to-do list so they could finish the product release. And that's too bad, because an otherwise solid product has this one weak link that will probably drive many users crazy, when it starts acting up anywhere from day one of ownership to perhaps years later.
Have you had a similar experience of a solid product brought low by an inexpensive standard part? Do you anticipate these things and tighten them up before the problem occurs on things you have bought and installed? Just as important, do you think about these issues in the designs on which you work??