[Drake] Drake R4B Passband Tuning Problem

[Bob Scott]

I have an R4B that I bought awhile ago and am just starting to look  
at.  It seems to have a problem with the passband tuning.

If I am reading the schematic correctly, if the passband selector is  
in the 4.8 position, the passband tuning circuit is bypassed.   
Otherwise, one of the tuned circuits is selected.

If I select the 4.8 position, I get lots of signal/audio.  If I switch  
to the 2.4 or narrower positions the signal level drops dramatically.   
If I try the passband tuning alignment procedure, I do not get much of  
a change in the voltage level at TP-2 which makes me think there is a  
problem in that area.

If anyone has any experience working on this receiver and can give me  
some ideas, I would be grateful.  My electronic skills are a bit  
rusty, but I would really like to fix this vs sending it out for  
repair/alignment.

73, Bob Scott W4ZY
Woodbridge, VA