[R-390] Smap Crackle, Pop, and fryhing eggs

[GENE BALINSKI]

ALCON,


    Need a little assistance.   My R-390 (non-A) has developed "frying-egg" and crackling sounds in the audio.  This is not minor. It completely disrupts the audio.  Band or mode does not matter.    I believe that I saw the S-meter move or jump during some of the crackling as well.  The noises comes and go, but is more constant now.   The noise does stop when I put the receiver in stand-by mode. 


   I have not tested any tubes or done recapping.   Given the above info, is there a better place to start troubleshooting ? 

Also could someone point me to any on-line manuals for the 390 ? 


73 and thanks in advance for any help


Gene K1NR