I picked up a few old plyprop caps on eBay very cheap the otherday and I've just got round to check the values with a meter (cheap maplin thing, but does me fine)
4 Solen MKP caps, I dont know the history but they're fairly clean looking.
There's three PB5000MKP (50uf/250v) and a PB3000MKP (50uf/250v)
Two of the 50uf caps show 33uf and 36uf on the meter (the other two are about right)
What do you think could have happened to them? and do you think I could still use them?
An externally hosted image should be here but it was not working when we last tested it.
4 Solen MKP caps, I dont know the history but they're fairly clean looking.
There's three PB5000MKP (50uf/250v) and a PB3000MKP (50uf/250v)
Two of the 50uf caps show 33uf and 36uf on the meter (the other two are about right)
What do you think could have happened to them? and do you think I could still use them?
Well 33uF is a lot more than 5% out 😉 so something is definitely not right. If I had to hazzard a guess, I'd say that they have probably been subjected to some nasty high currents (amp clipping if they were in a speaker) which have burned through some of the layers making shorts between them effectively reducing the capacitance, but this is a purely speculative guess not based on any real knowledge or experience in these matters 🙂
Tony.
Tony.
there were some Solen's about 20 years ago that went bad , but those had black epoxy end fill not red. yours are oct 1988 caps which could be bad from manufacturing problems or over currrent in what they were used for.
In either case I wouldn't use the 2 caps that measure low - and i'd be somewhat nervous about the other 2 given they are same date code and likley saw the same use as the 2 bad caps.
In either case I wouldn't use the 2 caps that measure low - and i'd be somewhat nervous about the other 2 given they are same date code and likley saw the same use as the 2 bad caps.
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