When I powered up my other PC last night, the monitor produced a nasty niff instead of anything on the screen.
More or less resigned to scrapping it, I opened it up to see if there were any bits worth salvaging - there was a nice cluster of toroid inductors that would be handy for a current project.
Then I noticed the blackened mains fuse. More out of curiosity, I pulled the power board and checked the MOSFET. That was OK so then the bridge rectifier - also OK. Having got this far, I wired a 40W bulb across the fuse clips and fed it mains, the bulb intermittently tried to almost light - and thick grey smoke billowed from the common mode choke.
Over the years, I've found a small number of common mode chokes damaged by a short downstream - but this is the first I've ever seen one of those chokes actually cause the fault.
Needless to say, the monitor got repaired and the junk box was deprived of some quite interesting components.
More or less resigned to scrapping it, I opened it up to see if there were any bits worth salvaging - there was a nice cluster of toroid inductors that would be handy for a current project.
Then I noticed the blackened mains fuse. More out of curiosity, I pulled the power board and checked the MOSFET. That was OK so then the bridge rectifier - also OK. Having got this far, I wired a 40W bulb across the fuse clips and fed it mains, the bulb intermittently tried to almost light - and thick grey smoke billowed from the common mode choke.
Over the years, I've found a small number of common mode chokes damaged by a short downstream - but this is the first I've ever seen one of those chokes actually cause the fault.
Needless to say, the monitor got repaired and the junk box was deprived of some quite interesting components.