"The vent is supposed to be the scored mark on the top and the plug at the bottom".
Most older designs used the scored topside as a backup. A few vendors used it as the sole venting means. But most just have the bottomside vent plug.
Between 2001 and 2003 the market was flooded with bad caps. The problem had serious impact on both MoBo and PSU vendors, among others. A lot of products containing bad or marginal caps are still out there.
At the time, it was written up in the Electrical Engineering Times and other trade rags. Rather than go digging for those old, dry technical articles, have a look at PCmag's Hushed-Up Disaster Dept.
To better help identify bad caps, be they on the MoBo or in a PSU, see the following:
• Bad System Board Capacitors!
• How to identify bad capacitors
The above have plenty of good close-up photos.
"Looks like I have 5 of them dead. 2 bulging, 2 leaking a little out the top and 1 where the bottom plug has been forced out".
Sounds as though your PSU was long overdue for replacement.
I read the vent bit on Wiki's Capacitor Plague page. Apparently bad caps been seen since 1999 and still used in some products made this year. Something to do with the formula of the dielectric which causes a build up of hydrogen before it pops. I'm sure that's what I heard happening.
The PSU was only 2 so I'm surprised it was so bad. I hope it hasn't damaged any of my new components. I guess I'll find out when I finally get my new PSU and RAM back.
"I read the vent bit on Wiki's Capacitor Plague page".
I hadn't heard it referred to as "Capacitor Plague" (at least not in the engineering trade press) but that phrase certainly turns up plenty of hits, including the Wikipedia page you mention.
"Something to do with the formula of the dielectric which causes a build up of hydrogen before it pops".
Over time, all electrolytic caps out-gas some hydrogen. It's a matter of degree. (i.e., how much and how fast).
"The PSU was only 2 so I'm surprised it was so bad".
It could also have been that "dust bunny" thing (excess heat build-up) or in combination with marginal or bad caps.
According to wiki again, the capacitors produce H instead of the electrolyte evaporating. I don't think I've ever had PSUs die so quickly, both Hiper ones, 2 within 5 years. Even cheap/case bundled PSUs I've seen longer than that.
The last one was a 580W but only did 360W on the 12V, not good according to a review. And THG did a PSU stress test in 2006 and the model I have failed: " the results were in violation of the specification." I think it may not be a very good one.
"According to wiki again, the capacitors produce H instead of the electrolyte evaporating".
Sorry to be somewhat pedantic, but parts of the article are poorly worded. As previously stated, all electrolytic capacitors produce some hydrogen gas. What they should have said is the improperly made ones produce it to excess.
While I like Wikipedia, and frequently cite it, just bear in mind that it does frequently contain inaccuracies. One of the early warning signs the author was sloppy is the inclusion of one or more "citation needed", "original research", or other similar notices. For a general overview it's fine. But if you're writing a paper for university or other important work, don't rely on Wikipedia. But do look at the references and the "last modified" date, as there is often newer research.
In this case, reference #1 (2004_Electrolyte_Hillman-Helmold.pdf) tells the story. See PDF page-1 (actual page 122), second column, the last four paragraphs, with the formula sandwiched between the second and third paragraph. If you're not interested in the details, just take note in the last of those four paragraphs of the words "excessive hydrogen".
"I don't think I've ever had PSUs die so quickly, both Hiper ones, 2 within 5 years. Even cheap/case bundled PSUs I've seen longer than that".
Thanks for the postmortem. Note to self: Never, ever, use a PSU from Hiper! Replace on sighting (or advise replacement) unless rightful owner owes me money! :D
I didn't mean to question your knowledge, everything I learned about the things was from that article (although I should know a bit about how they work from the university course I started) so it's nice to be corrected. So will all capacitors eventually pop/vent?
I did buy the Hipster PSU (exppecting it to be good quality) just before I moved into my house so it could be that my house has vast quantities of dust which are not friendly for PSUs.
I want my.computer back so I can play Skyrim :(
"I didn't mean to question your knowledge..."
I didn't even take it in that context. So no need for clarification. But, as you can probably tell, I've been at this awhile. I just didn't want you to assume the Wikipedia article should be taken at face value, no questions asked. (And in all fairness, I've periodically had my own share of brainfarts ;-)
"So will all capacitors eventually pop/vent?"
That should be "all [electrolytic] capacitors...". No, not necessarily. But at some point they will cease to function as the electrolyte becomes inert. Think of an electrolytic capacitor as a specialized battery. Their respective chemistries are not dissimilar.
For a non-defective part the main instigator of excessive out-gassing is heat. It doesn't much matter if it's externally or internally generated. If the ESR is too high, besides limiting the available surge capability, you will experience excessive internal heating, which is often the cause of premature failure.
"I did buy the Hipster PSU (exppecting it to be good quality) just before I moved into my house so it could be that my house has vast quantities of dust which are not friendly for PSUs".
While the excess dust may have been a contributor (and a good reason to consider a case with a removable, washable air filter) the THG review you cite should have served as your caveat emptor notice. :-)