The Stovebolt Site Forums The Shop Area The Electrical Bay The Radio Bench My orig. 46 radio....

I have my original under dash truck radio, had it playing on the bench some years back. It's on the shelf now and I want to do what ever is needed before installing. Also my truck is now 12v, what do I need to drop voltage to 6 v. for this old radio?

you need a dropping resistor on the + line to the radio - if you can find out what size, which depends on the current draw of the radio

Bill

JiMerit,
I have just been looking through some of the supplier's catalogs. They all carry a resistor but that may not be the best solution. Chevs of the 40 s have a regulated supply that will run all the accessories.http://www.chevsofthe40s.com/search.lasso?search=reducer&dept=truck

I must look at some electronic catalogs to see if there is a convenient 3 terminal regulator that is more reasonable in price. A 3 terminal regulator guarantees the correct voltage.

Correct, doing a fixed voltage linear regulator is certainly a better way to go for running a 6V radio off 12V instead of using a dropping resistor. There are a number of issues when using a dropping resistor with a vibrator radio although it will work to a degree.

The problem using a 3 terminal regulator is that they typically can't handle the current or power that is required for running a radio (appproximately 6.9V at 6 amps), which is going to drop about 40 watts across the regulator. The regulator pointed to from Chevs of the Forties is actually pretty reasonably priced if it is well built.

If you're comfortable around electronics and a soldering iron and you want to roll your own, you can use a standard 3 terminal regulator and add a pass transistor and a big heat sink to handle current and power needs. Here is an example that shows the general idea: http://www.mitedu.freeserve.co.uk/Circuits/Power/boosti.htm
Also, Linear Technologies makes a 3 terminal regulator LT1083 that can handle the current by itself. It could do the power too if you can adequately heat sink it.

To eliminate this adapter need altogether, I've decided to convert my radio to run on 12V by replacing the tubes, vibrator, and transformer with 12V equivalents which Delco used on the '53 - '55 Buick radios. Not a simple task but doable in a couple of hours and the results are cleaner IMO.

-Ed

Thanks guys, appreciate all the expert input. Since this truck is 12v. now I like the idea of converting the radio also. How do I determine the 12v equivalent tubes etc? This is a very small radio, so not alot of extra room for other components. Is there a tube supplier that can convert the components for 12v? Or is there someone that can do this job for me?

This is a great thread and I will be keeping Eds_53's material for my own reference.

Most of the people that repair these old radios can do the conversion to 12v for you. The tubes are generally the same number with the initial "6" replaced by "12". As a note of interest, those Buick radios have a tuning coil set which can be sustituted for the original in the 51 to 53 AD radio. This comes in very handy when you have a valuable radio with a broken tuning coil!

Back to this 42-46 radio, leaning toward swapping out internal components for 12 volt equivalents. Do you guys know of a supplier for these tubes, vibrator and 12v transformer? I can't imagine how many swap meets I'll need to attend to locate this Buick radio. Radio links on this site dont appear to sell parts.
Anything else needed???

don't forget the capacitors [which may be influenced by the specific tube requirements] - 12V solid state vibrators are fairly easy to find, but I can't imagine how many different places you'll have to deal w/ to find the correct individual pieces!
could start w/ watching e-bay, and there's a ring of old radio folks:
http://o.webring.com/hub?ring=antiqueradio

and here's places you might inquire:
https://secure.tubesandmore.com/
http://www.justradios.com/

have you made it work on the bench w/ 6V?

Bill

here is one of those radios on Ebay.
http://cgi.ebay.com/ebaymotors/Buic...741QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
I don't like to pay that much ($29) but the real killer is the shipping.
I use this site when I buy capacitors or need a schematic:
http://www.justradios.com/

Best of luck. You can get step by step help here if you wish.

Yes some years back this little radio played just fine on my bench, used 6v batt charger as power supply. Right now I'm just collecting input re. how to approach this job, not ready to dig in at the moment.
I've had some basic electronics, USN and some work at calibration lab. Light on theory heavy on melting solder and applying "the smoke test". My specialty back in the day was refered to as "Easter Egging", swapping components until you fixed it or it burned up. When sonar gear started making noise we'd head to the forward room with a box of tubes and began changing until noise went away. We also tested the torpedo fuel for quality, wouldn't want it to go bad.

BIG swap meet here in Turlock/olTruck CA end of the month, will be seeking that Buick 12v. Are there any other models that can also supply needed 12v parts, Chev,Pontiac, etc?
Thanks guys

Here's an idea to get the look of the old radio with the performance of a new one.

Gut the radio with the exception of the front so it remains unchanged from the outside. Then buy a new radio that comes with a remote control and bolt it in facing the other direction. Use the remote. It should fit fine considering how large the old cases are.