Thanks, Phil!
What I have is a very early PIN-5 switch (S/N 0018). I understand
that this evolved into the QSK-5, but I don't know what the differences are.
As this is an early model, I haven't much of a manual with this one.
When I purchased it in 1986 from Ameritron it came with two sheets of
installation instructions and two sheets that cover theory of
operation and the schematic. There are also about 4 pages of
pictorials for the installation in either an AL-80A or an AL-1200. I
have a replacement HV transistor that's used for switching and
replacement PIN diodes for both the rx and tx side.
I'll replace the fuse bulbs and make sure I understand what's
happening. I'll also download what I can from the Ameritron site and
see what I can learn from that.
73,
Kim Elmore N5OP
At 09:38 PM 1/31/2009, Phil Clements wrote:
> > Subject: [Amps] Internal QSK-5
> >
> > I have an AL80A with an internal QSK 5 switch (one of the early ones)
> > that I've had since new (S/N 095). For well over 20 years, it's been
> > working flawlessly. Recently, though, I had some 160 m antenna
> > problems under high power and blew the fuse lamps that protect the rx
> > PIN diodes. Blowing these is no biggie as it's happened before when I
> > mis-selected an antenna or has a switch set wrong. I replace them and
> > go on my merry way.
> >
> > WIth K3LR's help, may 160 m antenna seems to be going again. So, as a
> > final smoke test, I stated testing it under high power. But, this
> > time I'm seeing the fuse lamps light up when I transmit with more
> > that a few hundred watts on 160 m into a dummy load. I don't see this
> > on 80 m or any of the higher frequencies. As far as I know, this is
> > new, though I've never had much of a 160 m antenna and so didn't use
> > the amp it much down there.
> >
> > I'll check the schematic, but does anyone have an idea or two about
> > what might be going on?
>
>
>On page 5 of the QSK-5 manual, it tell exactly what is going on, and how to
>do a couple of tests to see what the problem(s) may be.
>
>What they do not mention is that if your problem is only on 160 meters, RF
>may be getting into the QSK-5 from the cables coming into the box. Some
>ferrites on the incoming lines should cure this, if your tests conducted
>from the manual show no faults.
>
>I have been a proud owner of a QSK-5 since 1999. I have used it at maximum
>rated power and also mobile, running a KW.
>
>(((73)))
>Phil, K5PC
>
>
>
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