Did some more work on this radio. Unusual for today it turned out to have a bad tube, the 12AL5 twin diode for the FM demodulator. One diode was weak to dead, thus the ratio detector didn't work right. At first I thought someone mucked with the alignment, so I added additional mucking
But as I couldn't get the demod to zero out, I started checking the circuit. And found the bad tube. Of course I can't find any 12AL5s, and a 6AL5 won't light up on 150ma string current. But this tube is at the bottom end of the string, and I decided to get more current for the 6AL5 heater by having it pass the "plate" current of all the set's B+ load currents. Just like how we have a #47 pilot light in parallel with a 35Z5 heater tap and have enough current to make the voltage across that 6V. So one side of the 6AL5 heater gets the powerline "ground" side, and the other side of that 6AL5 heater becomes the set's system ground. It works, but it does take twice as long for the 6AL5 heater to get fully warmed up as the other tubes in the set.
As this radio's chassis is very hot (a hard wire, not just thru a cap), I rewired the power switch to switch the powerline feed to the top of the heater string and rectifier tube, instead of switching the chassis ground feed side of the powerline. And used a polarized plug to have the chassis be close to real ground. Actually, with the 6AL5 kludge the chassis is about 6VAC above earth ground.