Felow Elecrafters,
I have just replaced the second-to-fail .01uF cap on the KPA/100 low band
filter relay circuitry of #5087. In this case, C13. Failure is a partial
short which allows that relay pair (k3 and k4) to close even though U2 hasn't
so
ordered. Symptom that this has happened is
6WLM
Date: Fri, 03 Apr 2009 10:29:59 -0400
From: Don Wilhelm
Subject: Re: [Elecraft] K2: KPA 100 Capacitor Specification?
To: jferg...@aol.com
Cc: elecraft@mailman.qth.net
Message-ID: <49d61d67.3030...@embarqmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
John,
I
John,
I have never found one of those caps shorted, and I believe the DC
rating on them is 50 volts, so they should have an adequate safety
margin since they are used in a 12 volt DC circuit.
I have trouble imagining a condition that would cause them to fail, but
then I recall that your 'shipbo
Bill,
While all you say is true, the inductive 'kick' should not be larger
than 2 times the applied voltage.
That is still a safety margin of more than 2.
73,
Don W3FPR
Bill Miner wrote:
> Don & John,
>
> When a relay is de-energized the voltage developed from the collapse
> of the magnetic
Is it possible you're setup is arcing inside the relay?
You're probably very familiar with shipboard environments and have taken
precautions so forgive me if I'm stating the obvious to you. I keep
remembering how often I've been knocked on my a$$ simply by carelessly
grabbing onto a disconnected
John,
If the voltage rating of these relay coil bypass caps is somehow being
exceeded in your shipboard installation causing the caps to fail, and if you
cannot find suitable higher DC voltage rated leaded replacements, you might
like to consider using SMD (chip) capacitors instead.
AVX includ
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