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  #31  
Old 07-22-2015, 06:33 PM
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Tubejunke Tubejunke is offline
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Originally Posted by NoPegs View Post


Well, sometimes it gives you 10µF and the WV of whichever cap out of the two in series isn't dead-shorted.


Generally though yes, two caps in series works like two resistors in parallell, if they're the same value you get half the capacity, if they're mismatched values you reach for the nomogram and/or slide-rule.
Hey thanks! Lots of good information. I still don't like the taste of that 10mfd in series with one of the other two. With old repairs you never know what someone was thinking. Someone may have heard that if you have a bad capacitor just tack another one in and all will be great. Would that be in series? Of course not, but they may have just tacked another in without that thought in mind. I myself used to parallel in caps leaving the old cap in place, but I no longer believe that to be a good practice at all for a number of reasons.

These schematic links posted here will be tremendously useful! I think the thing to do is look at the tech data and check the existing components for clues as to what may have been going on. Oh, and my box lid does have shellac looking stuff around it, but the interior bottom looks more dirty, oily, waxy......
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  #32  
Old 07-22-2015, 08:15 PM
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NoPegs NoPegs is offline
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Quote:
Originally Posted by Tubejunke View Post
These schematic links posted here will be tremendously useful!

No problems! Glad to help whenever I'm able to.

I went ahead and tossed up the complete operation manual if you or anyone else needs it.

I also dug out the best datasheet for the 1V or IV (eye-vee) rectifier tube. It mentions a value of anything 40µF or more needing special design in terms of inrush current limiting. However if you use 10µF caps like most of us are, that's only 10µF directly on the plate, the other 10µF has ~20K ohms in series with it, nothing to worry about there...


Quote:
Originally Posted by Tubejunke View Post
Oh, and my box lid does have shellac looking stuff around it, but the interior bottom looks more dirty, oily, waxy......
Drip some ethanol (aka denatured alcohol, not rubbing alcohol though...) on the stain, then daub it with a paper towel after 30 seconds or so. If your paper towel looks like you just wiped up a spill of cola then that's all shellac, and unlikely to be transformer wax... (Ethanol usually won't touch any of the waxes used for potting, it will however pick up carnauba wax to some extent...)
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  #33  
Old 08-02-2015, 01:37 AM
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Tubejunke Tubejunke is offline
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Quote:
Originally Posted by NoPegs View Post

Drip some ethanol (aka denatured alcohol, not rubbing alcohol though...) on the stain, then daub it with a paper towel after 30 seconds or so. If your paper towel looks like you just wiped up a spill of cola then that's all shellac, and unlikely to be transformer wax... (Ethanol usually won't touch any of the waxes used for potting, it will however pick up carnauba wax to some extent...)
Really as leaky as the filter caps were and knowing that some Ebay genius has applied wall current to it long enough to take pictures of the "magic eye" working and imply that it powers up great; I consider myself lucky that I have a working transformer at all. I love the one's who say the same thing if a pilot lamp comes on.

Everything on my unit works. Some bridge readings are dead on, then one will be too far off. Nothing is getting hot, but I know the tranny would have been hot quick on the filter caps I yanked with corrosion weeping out of the ends. Basically, I just don't like hearing my transformer to this degree. Are some 30s-40s transformers just louder in general? I wonder because my little Heathkit C2 also is quite noisy. The C3s I have are almost silent. I'm sure that wax in old transformers was in part to provide sound deadening properties & if it's gone perhaps you have what I have described.

I'm just sharing and gathering thoughts before I break out my Simpson 260 for current checks.
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