Bad Cap
Bob Quintal Inscribed thus:
Hammy wrote in
:
On Sat, 06 Feb 2010 12:50:06 GMT, Bob Quintal
wrote:
baron wrote in
:
Attached pictures of a capacitor failure in a 6 months old
computer !
Capacitor failure or solder joint failure?
Does the voiding on End 1 actually penetrate the cap?
Are you seeing the same picture. There is clearly a rupture on
the cap from internal pressue obvious from the way the case in
bent OUT.
When I look at the picture labeled chip-cap.gif, i see 2 horrible
looking solder joints. There is insufficient solder. The solder is
crystallized. There is insufficient solder in the meniscus.and it
shows evidence of insufficient heating I do not see any perceptible
bulging out of the cap at either end.
When I examine end-1.gif, I see what looks to be some excess solder
above the void, a horribly dewetted solder meniscus below the void,
and what look like a bunch of tin whiskers sprouting from the
meniscus.
The lighting of the capacitor is bad, failing to show detail of the
voiding, with a lot of reflection that masks the condition of the
meniscus.
The lighting is really hard to get right. Â*But there is a void between
the cap and the solder on each end. Â*The cap is O/C between the pads
and measuring on the capacitor metalization shows about 20 pf.
This suggests that the cap value is around 20 pf.
--
Best Regards:
Baron.
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