9-14B3 B
 You are able to hear signals in the voice/SSB mode but not in the SITOR (NBDP) mode. What is the most likely cause?
A. The phase locked loop circuit has failed.
B. The 500 Hz I.F. filter has become defective.
C. The R.F. amplifier has failed. 
D. The B.F.O. circuit has failed.
