[Elecraft] OT: Problems with Icom 756 Pro III internal tuner

[James Sarte]

Greetings fellow Elecrafters,

I'm sorry for emailing this question to the group, but the folks on this
reflector are a smart bunch.  Maybe someone could give me some advice or
suggestions.  I posted this question to the Icom 756 Pro III group and QRZ,
but no one seems to have an answer.

I'm diagnosing a problem with an Icom 756 Pro III.  It's tuner's "insertion
loss" is quite high.  For example, when the tuner is off, sending an
unmodulated FSK carrier shows the transceiver putting out 100W.  As soon as
the tuner is activated, power drops by 10-15%.  That's a lot of power being
dissipated somewhere, and I don't think it's good especially for 100% duty
cycle modes.  It doesn't matter whether the Icom is connected to a dummy
load or resonant antenna.  The results are always the same on every band.

In comparison, the K3's tuner seems to be incredibly efficient.  If there is
a loss of output power on the K3 whenever its tuner is inline, it's not
noticeable.  More often than not, power increases when the K3 finds a good
impedence match.

I've gone as far as recalibrating the Icom's tuner.  This was done by
terminating the remote jack on the rear panel, and entering the tuner
service mode.  The tuner calibration process completed with no errors
reported by the Pro3.

Any suggestions?  I'm going to call Icom support tomorrow to see what they
say.

-
73 de James K2QI
President UNARC/4U1UN