[R-390] BFO Question on Newly Acquired R-390A

[AE4CW]

Hello Group,
 
This is my first post after acquiring a R-390A last weekend.  The radio
plays well on AM, and all the basic functions seem to be in the ball park
except one.  The BFO is offset by about 9 KC from the carrier.  At the "0"
position the BFO tone is very high pitched.  Turning the BFO to the far
right reduces the frequency but still is very high pitched.  I concluded
it's 9 KC from the carrier by peaking the carrier of a BC station in the 0.1
KC BW position, then listening for the BFO and zero beating in the 16 KC BW
position.  Zero beat is very nearly 9 KC above the BC carrier.
 
I don't see any way to adjust the BFO frequency other than maybe L509 inside
the Z502 BFO can which I presume is factory set and not accessible.  Before
I head down a rabbit trail, can someone please suggest the most likely
problem(s) and best approach to diagnose and fix?  Perhaps the whole 455 IF
strip is off frequency, but that seem unlikely to me.  No measurements taken
yet, but I do have the Y2K documentation.
 
Thanks in advance for your advice.
---
Chuck, AE4CW