[Drake] Help me with Drake 2B

[Oasis3223 at aol.com]

I have  Drake 2B that works super on 80 and 40, but I hear nothing   on 
20-15-10, when I tune with the preselector... I imagine this is a simple problem,  
, any ideas I should try? I am thinking about selling the unit, it is very 
corroded, the  copper chassis needs to be taken apart and cleaned.  Cabinet is 
good, hears fine on those 2 bands. Why not on the others?
Bob