TCW
Full Member
Indianapolis, Indiana USA
Posts: 222
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Post by TCW on Jul 15, 2021 19:25:57 GMT
I am replacing a Black Cat, .033MFD, 1000V and I am looking to do so with a film capacitor. I was told by a salesman that a 333 K, 630G would work. I asked what did the underscore K meant and why is there was a dot under the 3 in 630? What does the G mean and how do I know if its rated for 1000V. He said he didn't know and could not explain. So I understand the capacitance code (see Capacitor Codes Chart below) for .033MFD is 333 if it was a plain K I would say it = ± 10% but its an underlined K so I don't know. As far as the 630 with a dot under the 3 all I can guess is 630 volts but as to why the dot who knows?. If it is 630V so this would pop before the 1000V needed. Does the 630 followed by a G = ± 2% or something else? Can anyone explain this? - Tom Capacitor tolerance codes: F = ± 1%; G = ± 2%; J = ± 5%; K = ± 10%; M = ± 20%; Z = + 80% / -20%;.
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Post by Ron Rich on Jul 15, 2021 21:03:24 GMT
Tom, Your "salesman" is fullOcrap-- You --NEVER-- can replace a cap with a lower voltage rating, type !! Sorry, I don't know what the "dots/underlines" signify.
If the old one was marked 1000 volts. the new one MUST be 1000 volts, or higher ! Ron Rich
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TCW
Full Member
Indianapolis, Indiana USA
Posts: 222
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Post by TCW on Jul 15, 2021 22:16:00 GMT
I'm thinking I need a lesson on how to read and spec film caps. I saw a guy replace a Aerovox .22mfd 400 DCWV 20% with a 224 K, 250A, dots under the 2&5.
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Post by Ron Rich on Jul 16, 2021 2:53:30 GMT
Hi tom, So, "guyz" do all kinds of "wrong things" ?? Ron Rich
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Post by misterv on Aug 1, 2021 1:27:54 GMT
With Tube circuits, Antique electronic supply/Amplified parts is my go-to. They list their film caps by voltage, and then you can select the desired capacitance. I know that voltage (or higher) is available in an "Orange Drop"...
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Post by bobtech on Aug 22, 2021 17:52:11 GMT
If you have a schematic to the capacitor under question, follow how it is hooked into the circuit. If it us a tube juke box the average voltage on the amplifier area of say 6ac7 is around 425vdc. As stated you can not place lower voltage, higher is better. Normally the caps state the working voltage. If you are working with electrolytic caps, observe polarity it is essential in hooking up a new ones If the circuit has previously been energized ensure that the Electrolytic are discharged. A VOM will help with any troubleshooting Hope this helps
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Post by Ron Rich on Aug 22, 2021 18:21:30 GMT
Hi Bob, Please read the "Hi Newbies" post in our FAQ's section-- It is taken for granted that one has the schematic for what he is working on, here ! Ron Rich
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