: Re: [TenTec] Sudden increase in power

[William F. Haddon]

 "Michael O. Hyder" <N4NT@chartertn.net>  Wrote:

>most Astron supplies are succeptible to RF
>interference in the regulator circuit and also succeptable to failure from
>voltage transients applied to the negative output. 

>Positive and negative  posts of the Astrons are floating above the chassis.

But not in all Astrons . . . . .

Last wkend, for 2nd time this year, had RF in my Astron RS-20A. On previous
occurrence  K1OJ correctly id'd p.s. as likely cause --ultimately traced to
a loose lead. The problem re-emerged -- frustratingly at the beginning of
NAQP  CW - so bad that coudn't operate for more than 2 qso's at a stretch..
So . . tore into the Astron immediately, and found that one of the nuts
securing the regulator board to the big surge capacitor was *slightly*
loose. Tightening it saved the contest.  

Note, however, that in this particular Astron  supply the neg lead *is* tied
to chassis gnd, as indicated in the circuit diag.  So the message is . .
don't assume you're home free if the neg line is grounded.  It's also
important to have all connections especially tight.  I will, from now on,
inspect the inside of this supply and the connections at the Omni rear panel
frequently.  Looks as if the 723 just goes wild with a little RF going where
it doensn't belong.  Otherwise, the Astron has been an acceptable companion
to the Omni V since its purchase, new, in 1990.

Comments on the refl. have been *most* useful and timely for me in this case.

73 Bill N6ZFO


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