[Yaesu] FT-100 DSP question

[Paul]

I recently acquired a FT-100 original, no "D". The rig works fine except 
that the DSP
notch isn't very effective. It barely makes a dent in a hetrodyne or 
tuner upper unlike
my 706MKIIG. The 706 takes it almost completely out. All the other DSP 
functions
work just fine. Was this a common problem with the first models? I have 
heard that
the early models had several mods/updates issued. Where might I find 
info that might
address this issue? Any help would be greatly appreciated.

Paul, N5PS