The case of an oil burner transformer is hot?? That will surprise the hell
out of millions of furnace owners and servicemen!
I guess his comment explains why he got it so cheap....
Carl
KM1H
----- Original Message -----
From: <rgroh@swbell.net>
To: <wa4tuk-rf@comcast.net>; <amps@contesting.com>
Sent: Friday, November 02, 2007 3:52 PM
Subject: Re: [Amps] Testing 8874s
> Barrie,
>
> There have a number of nice sources for information on hi-potting tubes
> etc. Here is one that addresses your question rather nicely:
> http://www.nd2x.net/k8cu-HV-tester.html
>
> 73
> Bob, WA2CKY
>
> ----- Original Message ----
> From: "wa4tuk-rf@comcast.net" <wa4tuk-rf@comcast.net>
> To: Barrie Smith <barrie@centric.net>; jeremy-ca <km1h@jeremy.mv.com>;
> Steve Thompson <g8gsq@eltac.co.uk>; amps@contesting.com
> Sent: Friday, November 2, 2007 2:27:41 PM
> Subject: Re: [Amps] Testing 8874s
>
>
> I would also be interested in guidelines for tube leakage using a
> hi-pot tester. My homemade unit will go to 10kv DC and I've used it to
> test
> some long stored tubes for leakage but interpretation of the results
> is only a guess. Metering is plus or minus 50 microamps.
>
> At what voltage do you test? At 2 times intended DC plate volts or
> maybe 4 times DC plate volts? Test between plate and grid?
>
> How high can the leakage be before the tube is unusable? How do you
> predict where it might flashover?
>
> How much leakage condemns a vacuum variable to the trash?
>
> The types in question are the typical kinds a ham might use 3-500,
> 4-400, 811, 813, 572b, etc.
>
> FYI, there is an article that Eimac (CPI) publishes on hi-pot testing
> of tubes. It is directed at very large tubes that need conditioning
> before use. One concept they talk about is de-barnacleing new tubes to
> flash away high points within the tube by controlled flashover.
>
> One surprising finding was how well my old collection of 5r4's fared
> and how well 1n4007's actually tested. (They tested well above 1kv
> before they even though about reverse flow.)
>
> Pat
> wa4tuk
>
>
> -------------- Original message ----------------------
> From: "Barrie Smith" <barrie@centric.net>
>>
>>
>>
>> > Highpot wouldnt hurt. I didnt mention it since it is not a common
> ham
>> shack
>> > item. The one I built around a sign transformer goes up to 13 kV.
>> >
>> > Carl
>> > KM1H
>> >
>> I have a high-pot tester that I've used for testing vacuum caps. I'd
> like
>> to use it to test various, mostly glass, tubes, as well. However, I
> don't
>> have a clue as to what the voltage used should be, nor what would be
>> acceptable leakage; or, between which electrodes.
>>
>> I've googled for information, but have come up short.
>>
>> Are there any rough guidlines for hipoting glass transmitting tubes?
>>
>> Barrie, W7ALW
>>
>>
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>
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