Zinc is most probably used for the film in these specific caps. They have been taken apart and analyzed by experts.
I had the notion that Galveston isle was a national center for accelerated corrosion and aging (too g.d. many festivals).
I don't even know who MSR is to look up their tech sheet, that might not be in English anyway. I liked "WVDC" as a marking, it was pretty understandable. I've since been trying to buy caps from Vishay rhoderon or sprague, or aerovox, whose stuff tends to come in made in USA, Germany, or Mexico, and whose markings make perfect sense. The Vishays even have little tails on the micro character, just like I was taught it in physics, none of this silly uF stuff. If I saw a datasheet in german, dutch, or spanish, I could probably read it.
H is the voltage code for 630 Volts. So marking 630H is redundant but fine.
K means 10% tolerance.
Often the above is on the opposite side that the value is printed on. Your 0.1μF should be marked "104" (10 * 104 pF), though sometimes you see 0.1u or 0.1μ or even 0.1m ("m" for micro? aweful).
There were Solen caps with black epoxy ends from about 87 which all went bad. The red end caps are earlier and the grey end caps are later. What the issue was in thier manufacture I don't know, but all the black end solen caps in my parts box and crossovers went low value. Never saw it in earlier caps or later ones.
I just measured 3 similar caps, all French, all black with red leads. Two were 100uf, one was 200uf. In my case, TODAY, one 100uf cap measured 3.5 uf. The second 100uf cap measured 0.52uf. The 200uf cap, interestingly enough measured 188uf, still sort of in tolerance. Any questions?
It certainly could. But there are many different standards for markings (which is to say there is no standard), so it is impossible to know what the markings really mean unless you know the manufacturer and look at their datasheet for that type of device.
As ticknpop wrote (and John Curl corroborated with measurements), I have checked my SCR caps and found that the 4 grey ends (2x 50uF and 2x 50uF @ 400V) all measured close to specified value. The others were 4.7uF red-epoxy ended (not black) caps but a mark suggests that all 12 of them were manufactured in '87. They were totally out of range. So it convincingly shows that the problem is a manufacturing defect.
Meanwhile, SCR France have replied, asking me to be more specific about values measured, but although I answered them back, they haven't said anything yet!
Meanwhile, SCR France have replied, asking me to be more specific about values measured, but although I answered them back, they haven't said anything yet!
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