[Amps] Answer about heat failure

[Ray, W4BYG]

Been reading the various posts on the subject of where most failures 
occur and wanting to add a little broader insight:

After more than 60 years in broadcast and cable TV engineering, most 
recently served 11 years as VP of Engineering for a satellite 
broadcasting network and now retired.

In addressing the issue of electronic equipment and systems failures, my 
experience has been that 55% to 65% (my estimate) of all the failures I 
have seen over the many years, were cable and connector related.  Cables 
over time being abused or cheaply made, cables/connectors improperly 
chosen or installed, or sealed from moisture intrusion, if needed.

Further note on moisture intrusion and to implode a common myth: water 
in itself seldom causes an immediate problem. Pure water is a pretty 
good dielectric.  But it can provide a path for contaminants to work 
their way into a connector, or cause ion migration between different 
metals and thence over time cause corrosion.  This often raises the 
resistance of a contact and in high current situations, cause the 
contact to burn up.  In RF applications SWR may rise (plus increased 
heat dissipation) and impair signal transport.

Excessive heat is not the basic problem, it is the result of a more 
basic problem.

Expected equipment heat removal has always been a concern, but in 
professional settings good engineering designs and practices usually 
have dealt with that sufficiently.  AR operators need to give proper 
concern for their installations.

Most manufacturers I have had experience with both professional and AR 
related, spend a good bit of engineering time designing and building 
their pet circuits.  They thus do a fair job of removing heat from their 
equipment.  AR "installations" can be another matter though...

What manufacturers can't control is where and how that equipment is 
installed.  It is important that due consideration be given to quality 
cables and connector installations and how the equipment gets fresh, 
cool air plus removal of the heated air, so it doesn't return to the intake.

Also, there is no shortage of "second guessers"  who think they can do 
things differently and thus think they can do a better job.  My father 
had a saying though.  He often expressed it: "a little knowledge is a 
dangerous thing".

Consumer and mass produced industrial packaged power supplies are 
another large area of concern.  They are often found in environments 
that they were not designed for, thus they can fail prematurely. "Bean 
counters" in many corporations insist their engineers buy cheap packaged 
power supplies from overseas and drop them into their often exotic 
equipments.  My experience has been that is a failure waiting to 
happen.  I recall having a $10,000 digital satellite modulator fail 
because of a $39 packaged power supply purchased from across the big 
pond.  Go figure...

But generally when there is a failure, one of the first things I look 
for is cable and/or connector problems.  If not there, I move on to  
power supplies.

BTW:  My career AR and professional, carried me from microwatts to over 
100 kilowatts.
73,
Ray, W4BYG


On 10/16/2016 9:37 PM, Riichard Neuman via Amps wrote:
>   While in fact true,  recent case studys have found that EHFAS (Excessive Heat Failure Anxiety Syndrome) have been found treatable in more than 50% of reported cases by installing a higher GPM water circulation pump in the patient's "less-headroom" amplifier.
>
> Richard  K3IPK
>
>   
>
>   
>
> -----Original Message-----
> From: Charles Harpole <hs0zcw at gmail.com>
> To: amps <amps at contesting.com>
> Sent: Sun, Oct 16, 2016 12:21 pm
> Subject: [Amps] Answer about heat failure
>
> The answer is TRUE.All failures of ham radios are caused, ultimately, by heat.Other suggestions......-vibration, which causes some component to break which cause othercomponents in the circuit to over-heat and fail.-component defect, or component just not installed causes surroundingcomponents to over-heat and fail.-operator mistakes which over-heat mis-adjusted circuits.and finally,-UPS-caused failures remain a mystery but customer anger is large source ofheat.Thanks to all who answered or just laughed.  But, don't make me ask "whatmakes a tube soft?"​73, signed in spirit of fun,​Charly, HS0ZCW_______________________________________________Amps mailing listAmps at contesting.comhttp://lists.contesting.com/mailman/listinfo/amps
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-- 
I'm no longer young enough to know everything!