Yes, but that would totally destroy my half-baked theory!
Mike, W4EF..............
----- Original Message -----
From: "2" <2@vc.net>
To: "Michael Tope" <W4EF@dellroy.com>; "AMPS" <amps@contesting.com>;
<nospam4me@juno.com>
Sent: Wednesday, May 30, 2001 4:52 AM
Subject: Re: [AMPS] care to take a guess..? Alpha problem
>
> >
> >Sounds almost as if the plate blocking capacitor is bad such that
> >the tank is only loosely coupling to the tube (that could explain
> >the weak dip, and the low output power).
> >
> /\ in my experiences, when transmitting capacitors fail they short.
>
> cheers, Mike
> >
> >
> >----- Original Message -----
> >From: <nospam4me@juno.com>
> >To: <amps@contesting.com>
> >Sent: Tuesday, May 29, 2001 7:38 PM
> >Subject: [AMPS] care to take a guess..? Alpha problem
> >
> >
> >>
> >> -
> >> Hello there,
> >> -
> >> A non amps member, Bob W0YVA Emails me with
> >> a problem he's having with his just purchased used
> >> Alpha A77. Care to take a stab with your opinion of
> >> the problem..?
> >> -
> >> I have directed him to watch the amps archive for
> >> your answers. Below is a copy of his text to me...
> >> 73's-skipp
> >> -
> >> [snip]
> >> : Here is what I have:
> >> : This is a "new" A77 (looks like never used) -
> >> : Serial 2556.
> >> : Seems to be okay except very low power output
> >> : (200 watts or so) with 80 watts drive. There is
> >> : plenty of grid current. Applying drive results in
> >> : significant plate current (800ma or so) which
> >> : can be dipped (the dip is very shallow) for
> >> : "max" power. HV reads normal. Power is
> >> : being measured with Bird wattmeter using
> >> : 5KW Bird dummy load. Problem appears on all
> >> : band segments.
> >> -
> >> : Here is what I have done:
> >> -
> >> : 1. Replaced 8877 with known good tube - no
> >> : difference.
> >> : 2. Checked bias directly at 8877 socket -
> >> : switches properly from high to low with
> >> : drive applied.
> >> : 3. The zener, D13, seems okay - checked
> >> : with ohmmeter.
> >> -
> >> : Where is the power going with all that plate
> >> : current? Weird.
> >> -
> >> : Suggestions for what to check? The plate
> >> : tank components all look good - no evidence
> >> : of heat anywhere.
> >> -
> >> : Any help would be appreciated.
> >> -
> >> : 73, Bob
> >> : W0YVA
> >>
> >> ________________________________________________________________
> >> GET INTERNET ACCESS FROM JUNO!
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> >>
> >> --
> >> FAQ on WWW: http://www.contesting.com/FAQ/amps
> >> Submissions: amps@contesting.com
> >> Administrative requests: amps-REQUEST@contesting.com
> >> Problems: owner-amps@contesting.com
> >>
> >
> >
> >--
> >FAQ on WWW: http://www.contesting.com/FAQ/amps
> >Submissions: amps@contesting.com
> >Administrative requests: amps-REQUEST@contesting.com
> >Problems: owner-amps@contesting.com
> >
> >
>
>
> - R. L. Measures, 805.386.3734, www.vcnet.com/measures.
> end
>
>
> --
> FAQ on WWW: http://www.contesting.com/FAQ/amps
> Submissions: amps@contesting.com
> Administrative requests: amps-REQUEST@contesting.com
> Problems: owner-amps@contesting.com
>
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|