[R-390] Re: Caps and more caps

Thu Jan 13 00:46:16 EST 2005

Um, could "it" be something as simple as Dallas' experience is several
years older than those that are starting to see age, among many other
factors, affecting what appears to be such different experiences ?

On second thought - NAH.

Dallas has to be right and all of us that work on thousands of pieces of
both old and new electronic gear for a living and have to replace
capacitors are just plain wrong.

Removing my tongue from my cheek: Quite simply I service equipment that
has NEVER - EVER left a climate controlled environment, quietly doing its'
specific job(s) and sitting along side other such equipment in racks. And
I replace capacitors all the time. Been doing this for over 35 years. And
I am paid to look at many such pieces of gear EVERY working day. I replace
may more capacitors than resistors, ics, transistors, etc. Capacitors are
a close second ONLY to the fuses I replace. And modern capacitors are MUCH
better made than the older paper ones.

(Fuses often need to be replaced simply due to aging effects. i.e They
often tend to sag over time and eventually break in equipment that
(almost) never gets turned off. Capacitors also show various
susceptibility due to a variety of factors. More on other factors
immediately below.)

Why is my experience so much different that Dallas and his friend?

Even the new stuff can fail repeatedly in ways; such factors as issues
during a manufacturer's specific batch runs, atmospheric control issues
during manufacture or stock storage BEFORE initial installation. I am sure
many of us can thing of MANY other such factors that Dallas simply has not
take into account with his simplistic math.

Dallas I appreciate all you have done for the r390 community to date. I
would prefer that my opinion of your talents remain focus on that and not
in your quite unbelievable argument(s) concerning capacitors. Yes it IS
possible to have your experience, but it is statistically too small a
sample  to have any meaning. As is your friends' experience.

Very best regards;

Bob Finch
w9ya

> You are right.  I wouldn't believe you.  Statistics say your claim is
> impossible, unless your R-390A was abused, which you say it wasn't.  The
> only one of your group that I believe so far is Cecil who admitted his
> R-390A with cracked brown beauties was rained on, et al.
>
>
> ----- Original Message -----
> From: <N4BUQ at aol.com>
> To: <r-390 at mailman.qth.net>
> Sent: Wednesday, January 12, 2005 9:33 AM
> Subject: Re: [R-390] Re: Caps and more caps
>
>
>> Well, if I still had the caps (they're residing in the landfill at the
> moment), I could send them to you.  But, then again, you might not
> believe I took them out of an R390A so it would be pointless.
>>
>> While I've never met him, I'd like to think Walter is a friend of
>> mine.
>>
>> Barry(III) - N4BUQ
>>
>> >What you and Walter have said violates the laws of statistics. That
>> is
> why
>> >I say I don't believe you.
>> >
>> >Are you and Walter friends?
>> >
>> >Dr. Dallas Lankford
>> >retired Professor of Mathematics and Statistics
>> >Louisiana Tech University
>> >
>> >----- Original Message -----
>> >From: <N4BUQ at aol.com>
>> >To: <r-390 at mailman.qth.net>
>> >Sent: Wednesday, January 12, 2005 7:29 AM
>> >Subject: Re: [R-390] Re: Caps and more caps
>> >
>> >
>> >> Again, I can only concur with Walter. A large percentage of the
>> "brown
>> >beauties" in my '56 Motorola had cracks that could easily be seen. I
> don't
>> >think mine was abused, but just old.
>> >>
>> >> Barry(III) - N4BUQ
>> >>
>> >> >Walter,
>> >> >
>> >> >I do not believe you. The laws of statistics say that if 7out of
>> 10
> brown
>> >> >beauties were cracked (as you claim), then my friend and I would
>> have observed several hundred cracked brown beauties. The odds of
>> us seeing
>> >none
>> >> >(which is what we saw) are way beyond 1 in a trillion.
>> >> >
>> >> >Dr. Dallas Lankford
>> >> >retired Professor of Mathematics and Statistics
>> >> >Louisiana Tech University
>> >> >
>> >> >----- Original Message -----
>> >> >From: "Walter Wilson" <wewilson at knology.net>
>> >> >To: "Dallas Lankford" <dallas at bayou.com>; <R-390 at mailman.qth.net>
>> Sent: Wednesday, January 12, 2005 5:04 AM
>> >> >Subject: Re: [R-390] Re: Caps and more caps
>> >> >
>> >> >
>> >> >> Dallas,
>> >> >> I keep a bag of old capacitors that I've removed from R-390As. I
>> randomly pulled 10 of the brown tubular ones out of the sack
>> this morning. I counted 7 of those with cracks. While it is
>> certainly
> true
>> >> >> that not all capacitors need to be replaced, I'd err on the side
>> of replacing too many than too few, especially if it is filled
>> with the brown tubulars.
>> >> >>
>> >> >> Walter Wilson - KK4DF
>> >> >>
>> >> >> Dallas Lankford wrote:
>> >> >>
>> >> >> >Perhaps you are shopping at the wrong R-390A store, but it is
>> far
> more
>> >> >> >likely that you are mistaken. I have carefully inspected and
> rebuilt
>> >> >> >between 10 and 20 R-390A's, and a good friend of mine has
>> carefully inspected and rebuilt well over 100. Neither of us
>> have ever found
> a
>> >bad
>> >> >> >(cracked or otherwise) brown encapsulated paper capacitor in an
>> >R-390A.
>> >> >> >
>> >> >> >
>> >> >>
>> >> >>
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>
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