Hi :)
I have found the FT_1000D has a fit with that problem
when RF is in the shack.
We found coax problems to this one.
Once we fixed it, we found no more problems with the
amp on (a commander 2500). I hope this helps you
73 STEVEN GRANT W4IIV :-)
--- Michael Tope <W4EF@dellroy.com> wrote:
>
> Hi Gents:
>
> I finally got around to messing with this leading
> character truncation problem a little.
> Wednesday, I swapped out the problematic FT-1000D
> with another FT-1000D. This
> appeared to cure the problem until I noticed that
> the autotuner was activated on the
> FT-1000D. When I turned off the autotuner, the
> problem re-appeared on the second
> FT-1000D. This was despite a low VSWR reading
> between the AL-82 and the FT-1000D.
> When I reactivated the autotuner, the rise time
> appeared normal. I then start playing
> with the drive to the AL-82, and noticed that at
> some point (~1400W output and 250
> mA of grid current), the truncation problem
> re-occured (this time with the autotuner
> activated). When I backed down the drive a little
> (~200 mA grid current) everything
> seemed okay again. Curious, I swapped out the
> FT-1000's again, and was able to
> reproduce the exact same behavior on the first
> FT-1000D (e.g. no truncation with
> autotuner on, and moderate PA drive).
>
> Any thoughts guys?
>
> Thanks,
>
> 73 de Mike, W4EF..............................
>
> ----- Original Message -----
> From: "Bert Barry" <kimba@sprint.ca>
> To: <W8JI@contesting.com>
> Cc: "Michael Tope" <W4EF@dellroy.com>; "AMPS"
> <amps@contesting.com>
> Sent: Sunday, March 25, 2001 1:25 PM
> Subject: Re: [AMPS] Problem with Ameritron AL-82
>
>
> >
> > That's a good point Tom, but I suggest cleaning
> both the switch pins and the relay
> > pins as well as the swich contacts. By a great
> coincidence, shortly after I posted
> > my note, my problem occurred again, after being OK
> for several months. (Last time I
> > simply reflowed the relay pins, and that worked,
> until now). This time I measured
> > the resistance at the phono jack with key down and
> found it varied all over the
> > place, from a couple of ohms, up to 50 or 60, then
> back down to 15 to 20, as I
> > jiggled the phono plug. I then took the bottom
> off and as soon as I touched the
> > relay (not the switch), the resistance dropped to
> less than an ohm. I then sucked
> > the solder off the relay pins, resoldered, and
> resistance seems to be less than an
> > ohm, and doesn't vary while jiggling the phono
> plug. But in view of your comments,
> > before putting the rig back together I'll clean
> and resolder the switch pins, and
> > spray contact cleaner on the switch contacts. But
> my feeling is that it's the relay
> > pins that develop high resistance or open circuit
> from the vibration of relay
> > closures.
> >
> > The only problem with this approach is that I'll
> never be sure which was the
> > culprit!
> > Mike, let us know how you make out, and your
> opinion.
> >
> > Bert, VE3QAA
> >
> > Tom Rauch wrote:
> >
> > > > I had exactly the same problem with my Alpha
> 87 driven by an FT-1000D.
> > > > The problem was not the amplifier - it was a
> fault in the wiring to
> > > > the "tx-gnd" phono jack on the back of the
> FT-1000. Fortunately, at
> > > > least in my case, the problem was NOT in the
> FT-1000 tx-gnd relay,
> > > > which would have been a pig to replace.
> > >
> > > This makes me wonder.
> > >
> > > My FT1000D has dropped the switch lead a three
> times now, and
> > > while it was on the way out it did something
> similar to what Mike
> > > described except on many occasions it would
> NEVER close the
> > > amp relay.
> > >
> > > The first time I just barely touched the relay
> switch near the jack
> > > and it cured the problem. The second time (about
> a year later) I
> > > resoldered the connections on the switch, and it
> was OK for a
> > > week.
> > >
> > > The third time I cleaned the switch contacts,
> and it has been OK
> > > for almost a year now.
> > >
> > > I wonder if the switches aren't the problem,
> since mine would
> > > straighten out just by touching it or anything
> around it??
> > > 73, Tom W8JI
> > > W8JI@contesting.com
> >
> >
> >
> > --
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> >
>
>
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