Are you SURE it's not oscillating on FM? Because if you are certain that it's not oscillating, the IF transformers/caps and later stages would have nothing to do with the problem.
If the problem is more accurately described as "being dead on FM band", then it's possible that one of the iF resonant circuits could have a bad component such as you have described. However, I think that I would only tear into the IF cans as a last resort- only after thoroughly checking out the 2nd IF amp and discriminator transformer/support components. I don't recall if you checked for plate voltage on the 2nd IF amp tube, but that's a good place to start. If voltage is OK on the 2nd IF plate, shut off the set and ohm out the discrim secondary- verify that you have resistance (schematic says 0.1 ohms) from end to end and from the center tap to either of the two ends. If that checks out OK, I think that I would replace the 5 uF/100V electrolytic cap across pins 5 and 7 of the discriminator tube- if only because this part has a high probability of failure due to old age.
One last thing before you rip apart the IF cans: you might want to check your work vis a vis the new capacitors/any other new parts. It's quite easy to end up with a misdirected connection or solder splash (I seem to be batting about 500 in this category) and they are often difficult to spot. I have developed a personal method to minimize this but errors still seem to creep in in almost every radio in which extensive component replacement is undertaken by me.
One future tip: generally I try to recap in stages. First, I replace the power filter elecrolytics, then power up the set and see how it works. If it is dead on one or more bands, I troubleshoot it before I move on to a wholesale cap replacement. Sometimes you will run into a "fatal problem" like a ruined bandswitch or dead IF transformer. These are of course repairable if you have the time and parts, but doing so is often a judgement call: most hobbyists have lots of old radios but very little time, so it may be better to admit defeat and scrap out a profoundly broken set if it has no real resale or sentimental value. But the trick is to reach that decision point BEFORE you sink a lot of time and money into it with a new set of capacitors. Just my $0.02.
All the Best,
Bill Grimm
This can be determined the same was as with an AM set. You place a working radio close to the one under test. The usual IF is 10.7 mHz so you should hear the oscillator at 10.7 above the frequency the set under test is tuned to.
"Hear" means quieting in this case. As you tune the radio under test you should hear the monitoring radio go quiet when you tune the one under test to a frequency that is 10.7 lower than the monitor set. Keep in mind that dial calibrations are usually not exact and that you need to tune either side of the expected frequency.
For example if the monitoring radio is tuned to 108, you should hear it go quiet as you tune the radio you are testing through 97.3 (108-10.7)
Thanks one and all for all the ideas....I have already tried the second FM radio, a portable and set its extendable ant near the 6BE6 oscillator and got nothing from either radio. The 6BE6 is brand new and so are the 6BA6's ! There is no 6AU6 . Ill try that measurement thing when I get done recapping this Crosley. I put the Coronado back together...I'm working on my kitchen table as we have no basement.
-Bill B.