[Chad Hauris]

I don't know if I would recommend aligning an FM set without a signal generator. I've tried it in a pinch but it usually ends up making the tuning too broad, where each station comes in over too large a position on the dial.

Garbled sound may be bad ratio detector diodes or a bad capacitor in the circuit.
Not sure if it uses a discriminator or ratio detector but if it is a discriminator it will have 3 if tubes and if ratio detector it will use 2 if tubes.
There is about a 5 to 10 mfd electrolytic in the circuit if it's a ratio detector and this may be bad if you have not replaced it. If it uses solid state detector diodes I would check those too (or check the 6AL5/12AL5 detector if it uses that). After these are ruled out you might try adjusting the ratio detector transformer carefully to see if any improvement is noted.

Also I would go ahead and replace filter caps to make sure you eliminate that as a problem. Sometimes there can be enough leakage to cause problems like low voltage to certain stages even though there is no obvious major hum.

Come to think of it we actually have this chassis at the shop though I don't remember what it uses other than the 12BA7. We haven't got around to fixing it yet, though. Also have another similar version but it is a transformer power supply chassis.