[TenTec] Argosy with AT-11MP

[807]

I've been using an LDG AT-11MP tuner with my Pegasus for several years,
quite happily and successfully.  A few months back I picked up a Argosy 525,
which got me excited enough to acquire a 525-D (the Pegasus "digital
display" and years of using Yaesu rigs with digital displays got me
spoiled).  However, with both Argosy's the AT-11MP tuner acts strangely,
with no power output showing until 10 or more watts is getting out.  I
thought the first Argosy I'd gotten had a problem, but could not find
anything other than an inability to sync my oscilloscope at outputs less
than 5 or 6 watts, and the newer Argosy II acts the same way.  The output
metering on the rigs and on an old Radio Shack SWR bridge show output
properly at all levels, and neither Argosy shows any DC current spiking or
excessive amps as the drive is increased.  When using the Peg instead of the
Argosy's, the power out is displayed at all power levels on the tuner, and
my scope will sync with the sampled output signal even at very low levels.
Use of a dummy load instead of the antenna makes no difference, and all
shack coax patch cables are new and homebrewed properly.

 

Has anyone run into this problem and researched it?  There seems to be no
problem with on-air reports and there is definitely a hearable QRP signal
out of both the Argosy rigs.  If it's not broke I won't fix it, but my worry
is that I've got some noxious parasitics that will eventually get me into
hot water, electronically or legally..