On Fri, 17 Apr 1998 10:48:36 -0600 "Richard W. Ehrhorn" <w4eto@rmii.com>
writes:
>Hi again Jon...
>
>I agree with Carl 100% on this one. Based on experience I'd guess that
>
>there is virtually zero chance that in your case a defective parasitic
>
>suppressor either caused, or resulted from, the cap arc.
>
>As others have already suggested, the tune or load cap is usually the
>"weakest point" when rf voltage is excessive. Maybe that's because cap
>
>plates often aren't perfectly aligned and spacing varies; a spec of
>dust
>between plates effectively narrows the gap and triggers the arc; often
>
>plates have sharp rather than rounded edges, and on higher freq bands
>(i.e., 21-28 MHz) where the plates many times are nearly "full-out"
>those
>edges "look at" each other, creating excessively high voltage
>gradients
>which increase the tendency to arc; corona is a function of frequency,
>so
>ionization of the air leading to arcing is more likely at the higher
>f's.
>Just some thoughts...my guess is that all these factors contribute to
>rf
>arcs at one time or another.
>
>73, Dick W0ID
Dick, thanks for your comments.
I earlier mentioned to Jon and others privately that a dirty amp is an
accident looking for a place to happen. I'm sure that in your business
you have looked at and shook your head at some of the stuff that has come
in for repair...and often by irate customers who dont have a clue about
PM, cleanliness, etc.
A vacuum cleaner is a valuable accessory in any ham shack...and so is a
no nicotine enviroment...or at least cleaning chimneys and tubes
regularly.
73 Carl KM1H
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