[R-390] Old Brown Beauty Statistics Lesson

[polaraligned]

You know what Dallas,  your statistics and retired professor BS is just
that.  I restored a early 60's Teledyne that had several cracked brown
caps just like Walter posted, and the kicker here is that the radio was
NOT abused.  It came to me in FINE condition.  All caps were tested on
a Sencore LC75 that was in good working condition and most caps were showing
 leakage.  You stupid college professors think you are high and might but
lack common sense half the time.  Book smart does not always apply to
the real world.  Maybe instead of ripping a fine gentleman like Walter
you should find the real cause of the discrepancy....like maybe you need
glasses.  Sad part is I used to respect you.  Now i think you are a Jerk.
Dan Arney is about as respected as anyone on this list and has rebuilt
many radios you call "Unrebuildable".  Is he a liar also?
We don't give a crap about  your math.  Maybe you should look for
other reasons for the discrepancies before you rip everyone here.
Do us all a favor and unsub yourself.

Scott


----- Original Message ----- 
From: "Dallas Lankford" <dallas at bayou.com>
To: <r-390 at mailman.qth.net>
Sent: Wednesday, January 12, 2005 9:20 AM
Subject: [R-390] Old Brown Beauty Statistics Lesson


> Disclaimer:
>
> "If you all are talking about those rained-on, snowed-on, sun-baked, 
> frozen,
> left in the parking lot for years, or otherwise abused R-390A's, then my
> remarks about capacitors do not apply to them.  I would not touch one of
> those with a 10 foot pole.  There are people who believe they can be
> rebuilt.  I don't.  I wouldn't buy any R-390A nowadays that I couldn't
> personally inspect before I bought it, or that didn't come with a return
> guarantee that it hasn't been abused."
>
>
> The fact that your R-390A was an (old) Motorola [see below] does not 
> change
> the fact that your claims violate the laws of statistics.
>
> Among the R-390A's that I have carefully inspected and rebuilt were two 
> 1956
> Motorolas.  Let's see...  how many brown beauties were in those two.  I am
> not sure.  There were about 12 each in the IF decks, and at least 1 each 
> in
> the RF deck.  That is a total of 26.  If on the average we would expect 
> out
> of 10 to be cracked (your claim), what is the probability that none were
> cracked (my observation)?  The answer is simple statistics.  Multiply 3/10
> by itself 26 times.  That is 2.5419 time 10 to the -14 power.  So the odds
> that I would observe none when you observed 70% cracked are 1 in
> 254,190,000,000,000.  This violates the laws of statistics.
>
> The above does not include a 3rd Motorola IF deck that I still own, in 
> which
> none of the brown beauties were cracked or bad.  If I included it, the 
> odds
> would be even more outrageous, namely 1 in 1.3509 times 10 to the minus 
> 20.
>
> BTW, both of those Motorolas are alive and well (about 20 years after I
> rebuilt them), with none of the brown beauties replaced (and none have
> cracked or gone bad in the meantime).  The only problem which has 
> developed
> in either is a switch which will not turn off in one of them.  The owner,
> who lives nerby, is too lazy to bring it by for me to fix.
>
> 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
>
>
> <cut>
>> 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
>
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