Had a no name brand battery charger come in for recycling. I set it up on the bench to test it. It powered up but after a bit it turned off. I took the thing apart. Pretty easy to do. Four screws at each end holding the slit extrusion case together and one holding a couple of TO220 packaged devices in place. The earthing was far from ideal. It was just tucked under a self tapping screw and none of the paint had been removed.
So of course the thing will not play up with the covers off! I set it up with a battery to check the charging. That all looked good.
(I’d better not mention here that I put the battery on with reverse polarity and blew the output fuse. Hey, I blame the fact that I did not have a black jumper lead. Yeah right!)
I moved it a bit to look at the front panel and there was a spark and it stopped working! “Oh s**t!” I thought to myself “what have I shorted out?”. Powered it up again and it still did not work. Better do some fault tracing. And then it sparked again. Ha! It is sparking in the Faston style connector. I was lucky that it had one of the clear insulating boots over it so I could easily see the sparking.
The connector had been crimped but the wire gauge was too small for the connector so they just soldered them. In this case there is a big solder blob that got nowhere near the wire. So it was a very loose connection.
Not only did they cut corners with thin wires but they also threw these things together really quickly. The solder hardly melted before they moved on to the next one. And there was probably no quality control or burn in testing.
Such a shame.
I did a decent job of soldering it and then added some proper earthing.