[Yaesu] ft990 comm problem

[vr2bg@harts.org.hk (VR2BrettGraham)]

If all to do with rig relating to CPU is functioning, then its clock is 
likely to
be okay.  And if it were off sufficiently far enough to cause TXD to be 
gibberish,
then it should equally have problem deciphering incoming on RXD.

Try comparing input versus output of whatever chip is used for line driver 
on TXD
line.

73, VR2BrettGraham