I have a 1954 F100 converted to 12V neg ground by the previous owner. I want to install an original Motorola radio. The radio is 6V positive ground. I know to use a dropping resistor to get to 6V but how do I change the polarity just for the radio. Thanks.

R Thorpe

 

Welcome to the madness. Here is what I found: http://lib.store.yahoo.net/lib/yhst-...034/radio-inst Maybe if no one here can come up with the answer you can check with http://vintageautogarage.com/ They seem to have a lot of 6volt stuff. I have been told you can't do the switch, but someone smarter than me will be along soon to agree or correct me. Good luck!

 

You can't change the polarity of the radio but you can isolate the radio frame/chassis from your truck frame by mounting your radio in plastic or some other non conductive material. Then wire up your B-plus to the radio frame and your B-minus to the radio input wire. You would also have to isolate your antenna mounting by mounting it in plastic and then mounting the plastic on the truck. I would imagine you would have t treat your speakers the same.

This should work. If anyone has any other input I hope they chime in. This may be more work than you are willing or capable of doing.

Quite a daunting task.

 

Only way I've been able to figure out, too. Mount the face and hide the working radio.

 

You can change the polarity of the radio very easily. In fact, if the radio still has a mechanical vibrator, you don't need to change anything; just put +6v to the power wire, and ground (-) the radio chassis.

Where you might run into difficulty would be if the radio has had the vibrator replaced with a solid-state one. If that's the case, you will need to replace the solid-state vibrator with either a mechanical one, or with a solid state vibrator made for negative ground.

 

I would put everything on a wooden table, including the antenna. Hook up voltage the original way and see if it works. If you have a shop, run it for a few days to see if it will work continously. Then reverse leads to see if it works. Save a lot of lost install time if it makes smokes. The old radios sound good when I was a teen in the fiftys, but now I don't know. I read somewhere that someone installed a C D player out of sight, but disconnected the on-off switch in the old radio and ran the C D input voltage wire through the old radio on-off switch. He also changed the old radio dial bulb to 12 volts to light it as if it was playing. What ever rattles your chain, I guess. chuck

 

Thanks Chuck,
I was planning just that, to run the setup on the bench. You know when I'm shifting that "three on the tree" it would be wrong to listen to anything but good old AM.

Richard