Re: FSP400-60GLN worth fixing?
The worst storage bulger by far is KZG (as far as Japanese ultra low ESR caps go), especially the 6.3V variants. KZJ comes close though (the 10mm diameter 6.3V variants), as might Sanyo/Suncon WF (doesn’t matter which variants). IMO, Rubycon MBZ/MHZ and Panasonic FJ/FJS/FL are generally the most reliable of all the ultra low ESR caps. Rubycon MCZ/MFZ aren’t terrible but they seem somewhat quick to vent from excessive heat. Sanyo/Suncon WG I have mixed experiences with, but the newer ones seem to fare better.
In my experience, late 2004 - early 2005 dated HM/HN/HZ aren’t as bad as those made in mid 2001 - early-mid 2004, but I’ve seen enough of them fail to avoid them altogether.
Don’t tell me... the one that measures 2700uF was the one you stored with a charge. 
In an electrolytic capacitor, the capacitance is inversely proportional to the thickness of the dielectric (although the surface area of the aluminum foil is also a factor). That means as the dielectric thins, capacitance increases, the breakdown voltage decreases, and vice versa.
Seems that way. In the now venerable Dell Optiplex GX240, GX260, and Dell Dimension 4300 machines, the 2200uF 6.3V Nichicon HM with bad datecodes have the highest failure rate on their motherboards, whilst the 1800uF 16V and 1000uF 16V Nichicon HM that filter the +12V VRM input, even with bad datecodes, are often fine even after many years of use. This might be because the 2200uF 6.3V caps are closest to the CPU heatsink, but I take it as more of an indication that the 6.3V caps simply age faster (although the +12V caps have to deal with much less ripple current).
The caps that had a negative charge on their plates were fine after you reformed them?
Originally posted by momaka
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but overall, I too have rarely seen failure. Like Behemot, I have a stock of about 200 or so total Rubycon MFZ and MCZ as well as Nichicon HN and HZ (all pulled from Xbox 360 consoles - i.e. used caps). I just opened my glass jars of them the other day as I needed a few, and noted that I had 2x Nichicon HZ 6.3V/2200 uF that had bulged by themselves. Upon closer inspection, both of these turned out to have a date code of H05xx, which is known to have some problems (though not as bad as H01-H04 datecodes).
Thus, I re-tested all my H05 HZ stock and found 2 more caps with border-line in spec high capacity (2700 uF) and one out of spec (3800 uF). This indicates some of these H05 HZs have started to break down. What's interesting is that I reformed and checked all of them roughly 2 years ago, and none had a problem. Some of them, I stored with full plate charge, while others I stored discharged in order to see if that would make a difference. But it didn't - one of the failed HZs was stored with a charge and the other was not. Same for the HZs that read high capacity.
In an electrolytic capacitor, the capacitance is inversely proportional to the thickness of the dielectric (although the surface area of the aluminum foil is also a factor). That means as the dielectric thins, capacitance increases, the breakdown voltage decreases, and vice versa.
Yes, you read that right, some of the 6.3V caps had negative charge on their plates from sitting in storage. This indeed indicates that lower-voltage higher capacity caps are indeed probably more prone to going bad in storage due to thinner oxide layer (or at least aging faster than their 10V and 16V counterparts).
But again, after a quick reform on some of these caps, I had no problem using them again.
Half of the computer problems is caused by bad contacts 
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