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Pyramid PIO vitamin Q type capacitor



 
 
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  #1  
Old January 16th 05, 04:13 PM
Adam
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Default Pyramid PIO vitamin Q type capacitor

Hi,

I have a 0.47uF Pyramid PIO vit. Q type caps but with one loosed lead
which connect to the aluminium casing. I have tried to solder the lead
back but what happen is there are some oil flowing out and become wax
once the solder cold down. After testing the cap with a digital
multimeter, the cap give me 1.14 uF instead 0.47uF. What's going on ?
Does the cap spoilt ?

Regards!
ADAM
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  #2  
Old January 16th 05, 07:18 PM
shiva
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"Adam" > wrote in message
om...
> Hi,
>
> I have a 0.47uF Pyramid PIO vit. Q type caps but with one loosed lead
> which connect to the aluminium casing. I have tried to solder the lead
> back but what happen is there are some oil flowing out and become wax
> once the solder cold down. After testing the cap with a digital
> multimeter, the cap give me 1.14 uF instead 0.47uF. What's going on ?
> Does the cap spoilt ?
>
> Regards!
> ADAM


Sure is. The thing is, Sprague Vit. Q's have no exposed aluminum case
(epoxy or something on both ends with center leads), and ... you can't
solder to aluminum - there are all kinds of ways of attaching leads to
aluminum cases (of *electrolytic* caps), all of them bein' pretty much
mechanical (crimping, spin welding (not true spin welding, more like
friction binding), even pseudo - spot welding, but soldering doesn't work.
Anyhow, this just a pedantic tangent, since it doesn't apply to the Vit. Q.
you've clobbered (if it was a vit Q).
If you're doing a slavish resto of a chunk of "vintage" gear, and the rest
of the parts are original, I have some .47 Vit. Q's, used, leads ~3/4 inch,
and I can send you one for the cost of shipping. Otherwise, I doubt you'll
hear any diff. substituting an orange drop.
'luck,
-dim


  #3  
Old January 16th 05, 09:15 PM
Al
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> I have tried to solder the lead
> back


You'll need special solder/flux to solder to aluminium!

> but what happen is there are some oil flowing out and become wax
> once the solder cold down. After testing the cap with a digital
> multimeter, the cap give me 1.14 uF instead 0.47uF. What's going on ?
> Does the cap spoilt ?


Yes.

Al.
  #4  
Old January 17th 05, 03:40 AM
Alan Douglas
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Hi,
I doubt very much that is aluminum; more likely tinned brass. But
it doesn't matter, as the capacitor is electrically leaky. The leakage
is fooling your digital meter into indicating a higher capacitance. In
reality, the capacitance hasn't changed. Take a known-good capacitor
and measure it while shunting a resistor of several megohms across it,
and watch the "capacitance" readout change.

As an aside, only Sprague made Vitamin Q caps. Lots of other makers
produced metal-cased caps with hermetic glass seals, and some of them
were junk.

73, Alan
 




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