I am using icom 706 MKII
on LSB, I get bad reports about
audio and modulation quality, and the output power is too low.
but on USB the output power is normal with good audio quality
and modulation!

Chafik-

Did you compare USB and LSB on the same frequency or on different bands? If
not on the same frequency, there could be other factors involved.

The IC-706 MKII may have USB and LSB mixing frequencies determined by the
microprocessor, so there would normally be no adjustment. About the only thing
you could do would be to try resetting the CPU, as someone else suggested. If
you do, all of your programmed frequencies will be deleted.

If the assumption about the CPU determining the mixing frequency is true, there
isn't much that can go wrong unless you happen to have a bad filter, or somehow
a CW filter is being selected when set to LSB.

73, Fred, K4DII