Try adjusting the 1400 kHz antenna trimmer. (You have to remove the front cover of the radio to access this adjustment.) It is the stand-alone screw adjustment closest to the tuning knob. (There are 5 pairs of adjustments to the left of it. These are the automatic presets. The frequency trimmers are above and the antenna trimmers are below.)
This adjustment works best if there is a station between 1360 and 1440 kHz in your area, especially if it's a weak station. It's best to make this adjustment as close as possible to 1400. However, if there isn't a station in your area between 1360 and 1440, any station between 1300 and 1500 will do. Don't adjust the trimmer to any station outside this range. The adjustment is designed to match the antenna's electrical characteristics to the radio's 1400 kHz preselector. In fact, if you ever replace the antenna, you should adjust all the antenna trimmers (including the automatic presets) to match the new antenna.
:The volume level is weak when using manual tuning. When the individual stations are programmed in, the volume level increases about 5x. Can anyone help?