[ICOM] 756 PII split prob??

[Mike]

Using MMTTY and a BuxComm Rascal.
Last nite I was trying to work RTTY on 40M split and just could not be 
heard. A friend told me I wasn't diddling, just sending a steady carrier.
Tried with amp off, no difference.
Re-set the RTTY parms and it worked for 2 calls, then went back to 
steady carrier.
Tried it simplex, steady carrier.
Tried it using XIT, and it was flawless.
Poltergeists?
Hints? Kinks?
73, Mike NF4L