Increasingly I am seeing more poor, questionable, or simply dangerous design in electronic goods.
I'm not sure if it's just because I'm getting older and crankier
Some things I've seen relatively recently:
1) A battery powered timer tap that had the diodes deliberately omitted from across the H bridge. This unit worked fine from the supplied alkaline cells, but blew up immediately some NiCads were used in their place. The lower internal resistance of the nicads allowed higher current through the motor and the inductive spike was thus larger and killed the H Bridge. There were markings on the board for protective diodes, but they were omitted. (OK, this is less a design flaw than a manufacturing shortcut)
2) Christmas lights for 240V operation that consisted of a strings of 20 various coloured LEDs and dropping resistors to limit the current to around 40mA. Sounds fine until you realise that the LEDs were consuming about 2W of power, and the resistors about 7W (and of course there were 4 strings of these). The resistors were covered in plastic (to insulate them from little fingers) but got so hot that they discoloured. The strings eventually stopped working, one by one, when a resistor fractured in them.
3) Torches using LEDs being driven from voltage sources, frequently using the cell's internal resistance to limit current.
4) Various USB equipment (hubs, card readers) that must have no protection from ESD and fail pretty much as soon as you look at them the wrong way.
5) Small transformer plugpacks that use non-springy contacts internally that are just pressed against the mains pins. One sharp shock and the metal bends rendering hte primary permanently open circuit.
The thing that annoys me the most about these things is that fixing the problem costs cents per item. These stupid little omissions probably mean more short term sales as people constantly have to replace them.
It's almost as if planned obsolescence has been overtaken by planned failure.
Does anyone else have any horror stories?
I'm not sure if it's just because I'm getting older and crankier
Some things I've seen relatively recently:
1) A battery powered timer tap that had the diodes deliberately omitted from across the H bridge. This unit worked fine from the supplied alkaline cells, but blew up immediately some NiCads were used in their place. The lower internal resistance of the nicads allowed higher current through the motor and the inductive spike was thus larger and killed the H Bridge. There were markings on the board for protective diodes, but they were omitted. (OK, this is less a design flaw than a manufacturing shortcut)
2) Christmas lights for 240V operation that consisted of a strings of 20 various coloured LEDs and dropping resistors to limit the current to around 40mA. Sounds fine until you realise that the LEDs were consuming about 2W of power, and the resistors about 7W (and of course there were 4 strings of these). The resistors were covered in plastic (to insulate them from little fingers) but got so hot that they discoloured. The strings eventually stopped working, one by one, when a resistor fractured in them.
3) Torches using LEDs being driven from voltage sources, frequently using the cell's internal resistance to limit current.
4) Various USB equipment (hubs, card readers) that must have no protection from ESD and fail pretty much as soon as you look at them the wrong way.
5) Small transformer plugpacks that use non-springy contacts internally that are just pressed against the mains pins. One sharp shock and the metal bends rendering hte primary permanently open circuit.
The thing that annoys me the most about these things is that fixing the problem costs cents per item. These stupid little omissions probably mean more short term sales as people constantly have to replace them.
It's almost as if planned obsolescence has been overtaken by planned failure.
Does anyone else have any horror stories?
