[Kenwood] TS-850 Problem

[WB9OST]

Just purchased a used TS-850S that is in need of some help.  I have everything working except that the receiver is dead above 22 Mhz.  At 21.999 Mhz and below it works and at 22.000 and above it is dead (Can not force a signal thru it even with a signal generator at full output).
I am thinking bandpass filter switching or 1st. RF amp switching or transistors.  Any one had this type of problem or can provide some info.

Thanks 
Loren WB9OST