[Elecraft] Board trace images - now becomes re-work of PC boards

Tue Apr 13 01:40:59 2004

I was wondering what the response would be to my throwing liquid oxygen on 
the fire :)  Where is that video of a college professor starting the 
barbeque with a little lighter fluid and a big bottle of liquid oxygen?  
The grill did not survive but the effects were phenomenal :)

I just think my radio works fine with out any sort of repairs.  From day 
one it has pleased me to no end.  I spend many hours a week hacking at 
software.  It gets designed in the beginning but the client always wants 
unforseen changes.  So the code gets to be a rats nest in no time.  This 
is another reason I don't want to use computers any where near my radio 
work.  It would be like a busman's holiday.  I want very large separation 
between work and play.  But soon that may not be true.  I am finding more 
interest in linking radios to computers while wearing my robotics hat.  
Sensor nets are also becoming very popular in many areas of research.  So 
my work my tend toward my hobby no matter what I do.

It is always interesting to see how opinionated a group of amateur radio 
operators can be.  Often times there are ten opinions for four people!
    Kevin.   KD5ONS

On Tue, 13 Apr 2004 00:18:35 -0400, Don Wilhelm <[email protected]> wrote:

> I too vote for that --- my K2 SN 00020 will be up to date electrically 
> with
> the most recent versions very soon.  I am in the process of adding the 
> K60XV
> and keyclick mods.  One of my professional experiences was with a large
> computer in the development stages, and the amount of re-work involved 
> was
> extremely high because we were pushing the envelope of the technology to 
> its
> limits.  Properly done, such re-work proved to be very reliable - as a
> memento of that experience, I keep a card that is fully populated with 
> logic
> modules and has a real maze of wires on its backplane - most of the added
> wires were the result of an 'after-design' requirement that it must 
> perform
> not only its intended function, but also be 'testable' by an automatic 
> card
> test system which was not consistent with the sequential logic functions 
> of
> the original design.  BTW, the card worked as intended without a problem 
> - I
> was unsucessful in getting the card test modified to properly test that
> sequential logic function (internal company politics - we don't do things
> that way), and had to change the card to conform to th e'standard' 
> testing
> procedure..
>
> The 'fragility' of the mods is highly dependent on the skills and 
> resources
> of both the designers and the implementers.  The designers have (IMHO) 
> done
> a fantastic job of telling us how to best lay out the added components, 
> but
> the actual implementation does vary from unit to unit.  I have worked 
> with
> several K2s where I felt the need to re-do the soldering and placement of
> the added transistors and other components because I felt there was the
> possibility that the added components could find contact with parts that
> they were not intended to contact or could work loose under vibration.
>
> It IS possible to add rework components in such a manner that they are
> mechanically stable (follow the designers directions to the letter), but 
> for
> some reason, components frequently are simply 'tacked' on and may become 
> a
> future problem.  If you are doing the upgrade mods, please follow the
> instructions carefully and you will end up with a reliable product - but
> failure to give foresight to what can happen with vibration or other
> physical handling will lead to a situation where 'bad things will happen'
> (phrase plagiarized courtesy of Tom N0SS).
>
> 73,
> Don W3FPR
>
> ----- Original Message -----
>
> I can appreciate your sense of esthetics, Kevin, but to suggest that
> jumpered boards are one bit "fragile" is not accurate. Not in any 
> practical
> sense, anyway.
>
> Having been involved with building one-off prototypes of everything from
> Ampex quad-head VCR's for the broadcast industry that were hauled around 
> in
> trucks to radar systems for the Air Force, I've seen countless pc boards 
> go
> into service in the field covered with cut traces and jumpers. Sometimes
> they had whole added circuits built sort of like what's now called
> "Manhattan" style hanging on the side. Some of them flew thousands of 
> hours
> - even in tooth-rattling piston-engined reconnaissance aircraft - and I
> never saw one that failed because the mods were "fragile".
>
> Personally, I have had a lot of my own gear with jumpered boards that
> rattled around in my car for decades without failure. Shoot, I have had a
> LOT of gear without a single PC board! <G>. Just a bunch of wires 
> soldered
> to terminals and to the sockets for all the vacuum tubes. When those 
> failed,
> it was most often a tube - sometimes a tube that was literally vibrated 
> out
> of its socket.
>
> My point is that, done right, there is no significant loss of 
> reliability or
> stability when cutting and patching PC board traces.
>
> Does my gear with the jumpers look like something that was replicated by 
> the
> thousands by Robots at a factory? Of course not. It looks like a "work in
> progress", which it is.
>
> To you it may be a kludge, to me it's a thing of beauty!
>
> And if you have an 'original' that's fine too.
>
> My point is that if were going to bet on one of our rigs breaking down, I
> wouldn't give odds that it'll be the modified one that goes first.
>
> Ron AC7AC
>
>
> -----Original Message-----
> Howdy Jim,
>     I built K2 #2511 a few years ago and have not changed a thing.  I've
> seen the inside of electronics with traces cut and jumpers all over the
> place and all I think is, "What a kluge!"  If I ever feel the urge to do
> the mods I'll get rid of faithful old #2511 and build a new one with the
> mods built in so they are not so fragile.  ...
>     73,
>        Kevin.
>
>
>
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