On Sun, 23 Nov 2008 14:42:25 -0800, John Larkin
wrote:

On Sun, 23 Nov 2008 22:38:50 +0000, Meee wrote:

I was wondering why vertical mounting electrolytics have like an
indented cross on them. The reason I ask is because there's 4 largeish
one around my CPU on the motherboard and they have all split open,
along the indentations.

It's a pressure relief thing. If the electrolyte overheats and boils,
the slits crack and a more explosive event is avoided.

John


I would add that all those he saw that were split are likely no longer
at their manufactured value.

Archimedes' Lever wrote:

John Larkin wrote:
On Sun, 23 Nov 2008 22:38:50 +0000, Meee wrote:

I was wondering why vertical mounting electrolytics have like an
indented cross on them. The reason I ask is because there's 4 largeish
one around my CPU on the motherboard and they have all split open,
along the indentations.

It's a pressure relief thing. If the electrolyte overheats and boils,
the slits crack and a more explosive event is avoided.

I would add that all those he saw that were split are likely no longer
at their manufactured value.

Especially with all the electrolyte evaporated ! Even without splits, I've
seen examples where the capacitance had dropped to ~ 10% of original value.

This can cause regulators to 'hunt' and blow the CPU by over-volting it.

Certain mobo makers - Gigabyte ? - now use only 'organic' type electros for
reliability.

Graham