[Radioroslyn]

As Ron mentioned you can unscrew #17 a couple of turns and see if that calms things down. Also there's a rivet on the 2nd 77 socket that grounds the cathode & surpresser grid thru a small metal strap. This rivet connection gets oxidized over the yrs and can cause hum and squeals. You could replace the rivet but it's in a tight place and it's a pitb. So what I've done is remove the IF adjustment trimmer above it and fit it with a ground lug. Cleaning the contact surfaces to insure a good ground along the way. Solder a piece of wire from the lug to one of the pins the metal strap is connected to. Job done. There's also a strap over on the 42 between pins 5 & 6 (cathode/ heater). If this rivet is a bad player it can cause hum. Just the run a wire between the two tubes to ground.

Once you get it to settle down hook your generator up and send a 460kc signal to IF. The osc doesn't have to be working to align the IF, it does to mix the pickup stations. It's important that it's on the nose at 460kc for good sensitivity and selectivity else the the performance is going to be poor... Good high emission 77's help a lot too.

GL