Just happen to notice the two other "magic smoke" threads and figured I would chime in as I also had my own little "mishap" earlier today.
So I was at the So-Cal Solar Store with my buddies Michael and Richard Ponce and the last time I had visited, Richard asked me if I could bring my laptop and Targus Auto/Air adapter this week as he wanted to try it out on the emergency power packs he was constructing and selling.
(The power packs consist of a Stanley 2 in One mobile work center with a 33 or 50 ah sealed lead acid battery in the bottom compartment along with a charge controller and some lighter sockets. The top was used to store cords and 12 volt lamps and there was a 30 watt solar panel mounted on the handle which could tilt out)
We first plugged it into an early unit he made 3 years ago that had an old 33ah battery in it and although it worked, the battery wasn't fully charged and ran down to 11.8 volts rather quickly. So I unplugged and he wheeled it outside then deployed the solar panel to recharge the battery.
I then decided hook up to a 50ah battery that he built more recently. However, one of the cigarette lighter sockets turned out to be wired backwards and I didn't know it. When I hooked up, I thought I saw a small bit of smoke coming from where the cord when into the adapter but though nothing until I realized the light on the adapter wasn't lit. I unplugged then decided to grab the multimeter out of the tool box and test the socket and that was when I realized the polarity was reversed.
Needless to say, the reverse polarity blew the adapter and it no longer lit up or charged the laptop even when we plugged into a correctly wired socket .
The laptop survived though and Richard is getting me another Auto/Air adapter to replace the one we blew.
Note to self, Check voltage and polarity before plugging into an unknown source.