Quote:
Originally Posted by Craig Sawyers
Or they are Chinese knock offs. At one stage they thought they were doing industrial espionage, but were fed with misinformation with an incorrect formulation for the chemistry, with the effect that their look-alikes failed in precisely that way. That was sometime in the 1990's IIRC.
|
Late 1990's, early 2000's. The incorrect formulation was that of low-ESR, low voltage electrolyte. Said espionage and sabotage took place in Taiwan mostly. Of course, modern Chinese capacitors of off-brands also don't always formulate their electrolyte correctly, but that's not a single high impact incident.
500V capacitors are sort of stretching the technology and use different foils and electrolytes. Depending on the manufacturer and voltage rating there are two or three main series of electrolytic capacitors that each use a slightly different technology. The 500V ones definitely don't use the same electrolyte as the sabotaged ones.
I think in this case, they failed for no particular reason other than being tired and/or of marginal construction. When axials were the norm, the seals sometimes failed in this manner as well. Mostly after many years of heavy use, though.
@joebog1: could you see if there's any date or other codes on the failed capacitors?