[R-390] R-390A restoration Questions

[Ian Gallimore]

 I am working on an R-390A which I purchased from Fair, and I wonder if I could trouble you with three questions which would help me greatly. 
1) When I select the 4 kc bandwidth, there is no signal. There is signal at all other settings, with the results that one might expect as the bandwidth is changed. Is it correct to assume that the 4 kc filter is faulty and should be replaced?
2) I have noticed that the RF Gain seems to function only in the last 10 degrees or so of clockwise rotation - that is, there is no signal below about 8 on the dial, and then the signal rapidly peaks as the pot is turned fully clockwise. Is this normal? If not, what should I be checking?
3) The carrier meter seems to be at Maximum regardless of the signal. Any suggestions most welcome.

Thanks for you help!

Ian Gallimore
VA3ODA