[Milsurplus] Research Help Requested

[Raymond F Chase]

I believe that the big push for investigations on electronics reliability
came during the Korean conflict when electronics complexity was growing to
thousands of components per box;  packaging created extreme heat conditions
and field shock and vibration exposure was not known or properly accounted
for.  ARINC started programs on reliability engineering and the "bathtub"
curve was introduced.  As for 6AK5's I worked on many radar sets in the 50's
that were chuck full of 6AK5's and I do not recall replacing few if any of
them.
I also heard WWII tales of SCR-522's and ARC 5 VHF sets being unpacked, set
out on factory floors or installation hangers and being totally retuned by
techs who had no idea what they were doing.  All the factory alignment was
shot to hell.  I experienced the same thing at shipyards where union workers
insisted that all equipment had to be completely tested and aligned in their
shops before installation as if nothing had been done at the factory.
Ray

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Michael Bittner
Sent: Monday, August 28, 2017 1:09 PM
To: Kenneth G. Gordon <kgordon2006 at frontier.com>; Milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] Research Help Requested

And how about, among other things, the acceptable characteristics of the 
6AK5 being variable up to +/- 65% ?

Mike, W6MAB


----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
To: <Milsurplus at mailman.qth.net>
Sent: Monday, August 28, 2017 10:02 AM
Subject: Re: [Milsurplus] Research Help Requested


> I've been reading that PDF that someone here gave us a link to, the Henney

> 1956 reliability
> report. I find it extremely interesting from several viewpoints and can 
> recommend it to any of
> us here.
>
> Apparently, no one who "mattered" was concerned in the least about 
> reliability of equipment
> during all of WWII, and it was only AFTER WWII that the reliability became

> a serious issue.
>
> I was only somewhat surprised to learn that up to 60% of gear received by 
> the military was
> unusable as received, for any of several reasons, poor packing being a big

> one.
>
> In one case, a piece of equipment had been tested at the factory to a 
> shock of 25 Gs, but
> when the stuff was shipped, the makers began receiving many reports of 
> defective gear
> upon receipt. A factory rep was dispatched to follow the gear from the 
> factory to its
> destination, and watched as the crate containing the gear was dumped off 
> the truck, 4 feet
> to a concrete floor. When the crate was opened, and a shock sensor was 
> examined, it was
> found that the gear suffered a shock of 35 Gs.
>
> Some things I found interesting was that something like 14% of aircraft 
> communications
> gear was affected, but that up to 84% of radar gear was affected.
>
> Believe me, those of us who are involved in safeguarding the remaining 
> WWII radio gear
> would do very well to read this entire paper. For one thing, it goes 
> heavily into the
> components used in our radio gear, and secondly makes some extremely 
> interesting
> suggestions concerning design.
>
> I intend to read it all, and more than once.
>
> Ken W7EKB
>
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html 

______________________________________________________________
Milsurplus mailing list
Home: http://mailman.qth.net/mailman/listinfo/milsurplus
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Milsurplus at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html