[R-390] New (to me) R-390A Can't Tune SSB

[Jerry Stern]

Just got a very nice R-390A and the receiver appears very sensitive but
I cannot tune in SSB signals. Weak or strong stations are just garbled
as if the radio is on the wrong sideband. I have checked for any loosely
seated tubes and the usual tapping around to see if I can find any
microphonics or signs but to no avail.  The BFO does seem to be
functional, at least to my ear, but I guess the problems would still be
likely in this stage?  I will start changing tubes but would appreciate
any other diagnostic advice.  I wouldn't bother the list for this
question but I cannot find any way to search through the R390 archives.

73 Jerry

K1JOS