[R-390] Reception BELOW 8 MHz Dead!

[Barry]

>Recently I tuned my R-390A below 8 MHz and the reception was DEAD. 8 MHz and 
>above was fine. The interesting part is the RF noise is still present, but I 
>am unable to get any stations even on strong local AM broadcast as if the 
>antenna was disconnected? When I turn on the CAL-BFO, You can barely hear 
>the CAL.. I was wondering if anyone can lead me in the right direction about 
>something unique about 7 MHz and below that would kill the RF gain, yet we 
>still have RF noise??? Thank you in advance! R-390A,  Motorola Built, SN 
>2937,,, WA6PHN 

Classic symptom of losing the signal from the first oscillator.

Barry - N4BUQ