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[Ed Richards]

The neutralizing procedure in the book does not tell you to disconnect
the 800 volts at the RF choke, and the screen voltage at the 680 ohm
resistor because you were not to have installed these parts yet. Look at
the end of the alignment procedure and you will find that is the time to
install them. For a completed radio they should be disconnected during
the entire alignment procedure. Good luck.

Ed Richards

On Mon, 7 Aug 2000 13:26:04 -0400 Marco Ciocca <marco at PA.UKY.EDU> writes:
> At 11:24 AM 7/31/00 -0500, you wrote:
>
> >
> >EK> Hi Marco, you haven't told us what all you are fighting on this
> 401.
> I must assume
> >it is a TX problem.  You ought to tell the guys what the fight is
> all
> about, whether on
> >one or all bands, what rx you have it hooked up to, pwr, out
> readings,
> dummy load
> >used....that sort of thing.  Have you looked at the service
> bulletins on
> Dale Wentz's
> >site??  http://members.accessus.net/~dwentz/kb9jja/heathkit/  There
> are a
> number of tech
> >bulletins onTX issues for the 401.  You probably should have given
> your
> tube tester id's
> >also.  I use a Heath TT-1A transconductance tester and could easliy
> have
> given the
> >settings for it.  6146B's have many variations (brands).  Tube
> tester or
> not, I would
> >highly recommend a spare set of GE's.  Some folks experience crappy
> operation with some
> >of the other brands.
> >
> >Just a few thoughts.
> >
> >Ed
> Ed:
>
> The transconductance tester I have is a I-177/B.  The problem I am
> having
> is apparent total lack of TX.
> The SB-401 is an e-bay purchase, so I know nothing of its former
> status,
> but it has the crystal pack installed.
> I also have a well functioning sb-301.
> I tried to just use the pair, but no TX at all (no grid  or plate
> current
> either.  Hv, however, is up at 800V).
> I tried to follow the alignment procedure as per manual, and I was
> able to
> peak the Het. crystals and the grid and the drive for all bands.  At
> this
> point the manual illustrates the procedure to neutralize the tubes
> for 29
> MHz operation.  I did get RF out at this point by keying down (the
> rf
> probe-VTVM vent out of scale) but, with me doing nothing, it went
> away.
> Thanks!
> Marco
>
>
> Marco Ciocca                            KF4URS
> Dept. of Physics and Astronomy          phyciocc at acs.eku.edu
> Eastern Kentucky University             Office: (606) 622-6172
> Richmond, KY 40475                      Fax: (606) 622-1399
>
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