On Sat, 15 Jan 2005 16:36:11 -0500, daytripper wrote:

On Sat, 15 Jan 2005 08:42:09 -0800, John Larkin
wrote:

On 14 Jan 2005 22:19:26 -0800, "larry moe 'n curly"
wrote:

Several months ago, a port on an NEC-based USB card failed (a section
of its LM3526 power controller & overcurrent protection chip blew), and
just recently the same happened to an ALI-based USB card. I'm pretty
sure I didn't zap either card with high voltage because I always touch
the outer metal shell of the USB connector to bare metal on the
computer case before plugging it in.

Each USB port has a 100-220 uF aluminum capacitor across its +5V and
ground lines, and the NEC-based card also had a ceramic chip capacitor
in parallel. Is there anything I can change or add to protect USB
ports better? Does it help to use tantalum or low ESR aluminum
capacitors? I installed tantalums on my other USB cards just after the
NEC card blew.


Tantalum caps are inclined to explode.

That's a mischaracterization.

When they *fail*, they tend to 'splode.
But they don't tend to fail if the application is appropriate...

....and you don't buy ****. They do get grumpy when inserted backwards
though. That was the real problem thirty years ago. Tants are expensive
though and thus the cheaper leaking aluminums.

--
Keith