I had a HP-laptop charger that developed a screeching noise -- it sounded like a slow-rotating fan that could use some oiling. It didn't explode, but it caused

I had a HP-laptop charger that developed a screeching noise -- it sounded like a slow-rotating fan that could use some oiling. It didn't explode, but it caused the laptop to crash hard a few times (the screen just got garbled) and, needless to say, didn't provide the power required to charge the batter.