Hardware Insights Forum

Wester547 wrote:Remember the Aerogel "super capacitors" clock capacitors that were notorious for leaking in the original Xbox? They were only rated for 1,000 hours at 70*C with a maximum temperature of 70*C. Yes, 70*C. Look at the datasheet. Coupled with those crappy circular bungs they used, no wonder they failed prematurely... (at least inconsistently - the ones I pulled had bullseye bungs)

Well in that case, I fail to see what advantage they provide over good old CR2032 button cells.

I know that ceramic capacitors can crack and go short-circuit under mechanical stress, and that tantalum capacitors don't take well to surges. So far neither has failed me, though.

LongRunner wrote:Well in that case, I fail to see what advantage they provide over good old CR2032 button cells.

The 1.6A/1.6B Xboxes switched out the Aerogel cap for a Nichicon "EVerCAP" UC series capacitor (datasheet) which was also rated for 1,000 hours @ 70*C but at least those capacitors had bungs with thicker rubber so they were less prone to leaking over the years (though they weren't as low ESR as the Aerogel capacitor - 2 ohms vs. 0.4 ohms - don't know if it matters in that application, though, I think capacitance and of course voltage is more critical). Those series were actually double layer capacitors so I think they use quaternary ammonium salts for the electrolyte. Unfortunately the 1.6 Xboxes do need the clock capacitor to POST. I also agree that 400W is probably the limit of the PSU in the first post with a 35 size transformer.