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@gmail.com>
To: amps <amps@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@contesting.comhttp://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
--
I'm no longer young enough to know everything!
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|