Replace electrolytic caps first. Loss of capacity can lead to oscillation.
When electrolytic caps have been replaced and tube shields are in place slightly detune an IF Transformer if squeal is still there. You have the radio peaked up well giving too much gain causing unwanted oscillation.
Norm
:Hi, all: My Crosley has a problem I can't seem to solve. With most stations, it must be tuned in dead on or it will squeal. It goes from a high pitched squeal down to a low growl the closer you get to the station and if you can get it exactly tuned it, you don't hear it. It doesn't make the noise between stations. I have replaced all the paper caps and checked values of resistors. Other caps are listed as mica. I plan on replacing the electrolytics (had to order some more) because one appears original (checks out good with cap tester) and the other was replaced at some point and checks out a little below it's rated value. The radio doesn't hum, though. All tube shields are in place. An alignment seemed to help, but not eliminate the squeal. Mark from Kalamazoo