[Kenwood] TS-850SAT - Curious Fault.

[Mark Capstick]

Dear All, 
I have a TS-850SAT with a curious fault. The symptoms are as follows: 
If the radio is on VFO B, on a frequency BELOW 10.000 MHz, and the HIGH CUT
SLOPE TUNE control is moved off its fully clockwise (In-active) end-stop,
the frequency of VFO B Jumps DOWN 1MHz.
VFO A is not affected. 
Frequencies above 10.000 MHz are NOT affected. 
If you try and move back up 1 MHz to the original frequency, with the UP
button, the radio "beeps", but does not move the frequency, until the HIGH
CUT SLOPE TUNE is moved back to its clockwise end stop, when it operates
normally again.
Has anyone ever seen this problem before? Any help would be welcome. 
73, 
Mark, G4RCD 
PS. I have just joined this email list, so apologies if this has been
discussed before.