[R-390] Humm problem,

[Charles B]

Hi all,

Any ideas on the following problem.  When I turn the R-390A 
on and wait until it warms up, I get nothing but a Humming 
sound in all three positions: AGC, MGC, CAL?  There are no 
signals.  This happened unexpectedly when I turned the 
receiver on one morning.

Thanks

Chuck