Allen,
The stiff PTO knob is because it is a Permeability Tuned Oscillator, (PTO).
That is, it is a slug screw being turned by the knob you turn for tuning.
Thus, it is like any lead screw with a positive "feel". It does help keep
it on freq . in mobile, but is a fundamental character of a PTO which is
directly driven by the knob.
The feedback is RF feedback, and you should turn down the mike gain until
the ALC green LED only flashes on voice peaks. It should NOT stay lit in
SSB! This should correct it. It can happen if you have a bad coax jumper
to the dummy load, like a cable with poor shield coverage, as well, or bad
connector solder joints. Another way is if the rig is set upon a tuner
case. Keep them side by side. Most tuners do not magnetically shield the
coil adequately if at all, and it can couple into a rig of any model. Been
there, done that!
Usually, the problem is the mike gain too high. With Ten Tech hand mike,
mine only has the gain at second from left dot on the knob. Another
contributor to RF feedback could be the coiled cord on the mike having
inductance, especially, if at the same time a key or bug is plugged in with
a coiled cord. I had this happen at Field Day!
Try turning down the mike gain, and watch the ALC LED and let me know if
that fixed it. The other thing, if this is a used ex mobile rig, is to go
inside and tighten all grounding screws, or loosen and retighten, to get
clean bite on the lock washers to chassis and ground plane of board.
GL and 73,
Stuart K5KVH
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