Power Supply Horrors
Contents
This summer I've witnessed the death of a number of power supplies; some of them were worth sharing.
USB Hard Disk Adapter
A few months ago I've bought one of those small adapters from various hard disk bus interfaces (IDE 3.5", IDE 2.5", SATA) to USB at an electronics fair. I was happy with the way it worked, so at the next opportunity I've bought another one, this time with a different box. They both came with a reasonable looking power supply with 12V and 5V on the usual hard disk connector.
When I was using the new one for longer than usual, I heard a crack noise: I first thought that the hard disk had died (it was an old one), but after a bit of post-mortem I realized that the power supply was dead, and I've opened it expecting to change a dead capacitor or two.
This is what I found.
The noise I've heard is perfectly compatible with the crack in the plastic casing of Q3; what I still can't explain is why there are components rated e.g. 50V on the 220V side of the circuit, and basically how could it ever work, even for a short time.
As soon as I've checked a few values, I'll add a picture with all of the component codes I can identify.