[Kenwood] TS-440S shaft encoder query

[Jack/AE7DX]

I have just encountered a problem with the shaft encoder on my 
'440S...the thing froze up today (while demoing the rig for a 
prospective buyer!) with no prior indication of impending disaster. The 
shaft can be rotated only with extreme difficulty. My question is:

Is this a common problem with a known fix, aside from replacing the 
shaft encoder (if replacements are, indeed, available)? I have partially 
disassembled the front panel of the rig and see that getting to the 
encoder will be a daunting task so I'm hoping for suggestions before I 
am forced to continue.

Thanks,

Jack, AE7DX