[codefox1]

Back in the old days, when my dad sent his old Packard to the bone yard, I took the radio out the night before. Of course I didn't know what I was doing, but I took an old television power transformer, connected the 6.3 volt windings to the tube heaters, removed the vibrator, and hooked up the h.v. from the old TV transformer to the plates of the 0Z4, at least that's how I remember it. To my utter amazment the radio played very nicely. I was around 12 years old at the time.

But if I were going to restore more than one or two of these beasts today, and they were going to be put back in an antique with a 6 volt system, I think I'd get a 6 volt car battery, (needen't be all that good, just safe.) and make a little trickle charger to keep it up. Then I could fix the D**n things in my nice warm basement, rather than in the garage.
(Disconnect the trickle charger offline when using the battery to power the radio.)

Key locks are not hard to come by, of course probably not exactly in the same shape and size as the original. I suppose the ones you are talking about are kind of like the keys they used on old Hammond Organs (yes, I have one, no I don't have a key, and yes, they were all the same, and you can get one for a few bucks.) If I still had rug rats inthe house, I might have gotten one.

If a key operated the radio and the ignition, I suppose the lock would be designed so you could turn on the radio, remove the key with the lock in the "on" position, then use the key to start the car. But wait a minute, then if you turned off the engine, the radio would still be on, and drain the battery.

Ron, I know you will read this, and you are studying computer science, you have probably heard, or will soon the phrase
"The key, the whole key, and nothing but the key so help me Codd" Nothing to do about auto radios, it is about the third normal rule in database design. It's a lot nicer than the rote resistor code mantras.