On Mon, 9 Jul 2012 02:11:30 -0700 (PDT), Ron
wrote:

I bought a 90 watt power pack/battery charger for my Dell laptop and
less than 3 months later whenever I plug it in, something quietly goes
"pop!" Probably a cap inside? I think the unit still works, but it
makes me nervous to use it.

Does this mystery charger have a model number?

It's not going to explode or anything like that. Most likely, if
there is something wrong inside, it will simply stop working, usually
at the least opportune time.

Are you SURE that it didn't go pop for the first 3 months? If so,
something has probably broken loose inside the charger. If the pop
sounds like an electrical arc, it's possible that the high voltage
section is drawing an arc on startup. Some like an annular ring
around the switcher xformer leads on the PCB or one of the hi-v
capacitors might do that. Internal arcing inside the xformer is
another.

I doubt it's fixable in that almost solid
plastic case, but is it really safe to continue using or should I
ditch it and buy a new one? Opinions anyone?

If it's been only 3 months since you bought it (from Dell?) it should
still be under warranty. Rather than worry about it, try to get it
exchanged under warranty.

It is possible to open the case, but it's not easy. What you're
likely to find is a solid block of electronics, magnetics, heat sinks,
and wires, all encrusted in difficult to remove silicon rubber. Unless
you've had some experience dealing with switchers, I would not attempt
to repair it. (Hint: Use an isolation transformer).

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558