Father-in-law purchased a aftermarket radio that meets his needs for his 1976 Warlock (D100). Only complaint that I have seen in this particular radio is a complaint of the radio not booting up when the car is started quickly. They mention the key needs to be turned on, then started. I'd like to cure this problem before installing it.

From what it sounds like it is caused by the "switched 12v" source not letting the radio start up and it locks up. I figured by piggy-backing off the ballast/coil wiring I can resolve this. Since then the radio would be powered while cranking as well. (Which I know could be a concern in dying battery situations, but the small current draw doesn't concern me. And the vehicle is well maintained.)

Problem with that is full voltage would then be fed to the coil positive versus the dropped voltage it is designed for. Anyone have diode information on what I am looking for? I understand the concept, but do not know what style/size/rating/etc I am looking for.

Any advise?

Thanks-

This is a new one on me. What radio has he got that would take all this abnormal wiring work?

why not Tap into another switched 12v source out of the fuse box? test light will show you a constant switched 12v source while starting it.

problem i see where you want to tap it from is feed back.

How about an rc network? Just add an relay then have the coil charged though rc network that turns on the power at your desired delay.This is simple and will keep the existing wiring in use.

The diode will work but I would rule out all other fixes first. You will need a diode that is rated at least as high as the radio's fuse.( no harm in a bigger diode) 5 amp fuse = diode that can handle 5 amps. 1N5402 is a 3 amp diode from Radio Shack, you can tie them together in parallel to get a higher amp rating.