11 Sep 2003, 01:41, Greg Easthom (1:153/7715), wrote to Matt Mc_Carthy:

Hi Greg.
......................

 GE> "It didn't have the right additives," says Dennis Zogbi, publisher
 GE> of Passive Component Industry magazine (Cary, N.C.), which broke
 GE> the story last fall. According to Zogbi's sources, the capacitors
 GE> made from the formula become unstable when charged, generating
 GE> hydrogen gas, bursting, and letting the electrolyte leak onto
 GE> the circuit board. Zogbi cites tests by Japanese manufacturers
 GE> that indicate the capacitor's lifetimes are half or less of the
 GE> 4000 hours of continuous ripple current they are rated for.

I wonder how many here are aware of, or realize the impact of that
statement?  It _IS_ a standard rating throughout the industry!

Samsung capacitors are rated 'honestly' at 1000 hours continuous ripple
current _AT_ rated voltage, 4000 hours at 50% rated voltage.  

That 4000 hours means that anyone running a computer 24/7 can anticipate
failures after a mere 166.6 days!  The keyword here is "rated
voltage".  The caps that have been failing here are 6.3V rated, and
running at +5V.  That's too close to the "1000 hour lifetime",
and I would _expect_ them to fail near that time (a measly 41.6 days!)

For that reason, I've been replacing those caps with 3X voltage caps, and
often 'shoehorning' them in.  

With boards 'shrinking' so fast, there's often not much a board
manufacturer can do, so they are forced to 'fudge' on 'headroom'.


     Good luck...  M.

--- Msged/386 TE 06 (pre)