The Stovebolt Site Forums The Shop Area The Electrical Bay The Radio Bench Elecrtical connections for 47-50 radio ?

I have a 47-50 Chevy truck radio that has 2 new electrical supply connectors. One goes to the on-off-volumn switch and the other shows no resistence to ground. Do I simply connect positive to the on-off switch and negative to ground ?
The radio also has new push buttons. They push in but do not move the dial ?

I believe you'll find one is power [+] and the other is to the speaker - ground happens thru the case from the mounting - for the dial, you'll hafta open it up and look - may be broken string

Bill

The speaker is in the radio. The dial moves fine with the tuning knob.

Rusty,
you have a radio that is growing in value every day! The last restored one that I saw sell on Ebay went for $760 !!

Originally there were two electrical supply leads coming out of the case, one for the dial lights and the other to run the radio electronics. The lead for the light is not fused and it gets connected to the "dash light" connector on the headlight switch. The other lead should have an inline fuse and it can be connected to the load side of the amp meter.

You are correct that the speaker is inside the radio.

It is very unusual to have the buttons moving properly but not moving the dial. I wonder if the buttons are all set to the same spot on the dial. Try tuning the dial to a different location, pull on a button while exerting some force to the left. The button should come out almost the depth of the plastic. Now push the button in all the way and it should be set to the new dial location.

If you haven't powered it up yet, you may want to look at the suggested procedure in the tech tips.

truckernix, I re-set all the push buttons as suggested, and they all work properly. Thank you.
Both electrical connections on the radio are new and neither is fused. One connection goes to the on-off switch on the radio and the other connection shows no resistence to ground when tested with an ohm meter.
I will follow the excellent procedure in the tech tips and use the frame for ground connection but the connection that shows no resistence to ground would accomplish the same ground, yes ?
Is the electrical connection for the internal light connected to the on-off switch as well ?
There is also an electrical probe hole on the lower right hand front corner of the radio. What is the purpose of that hole ?

Rusty,
that is good news!

That extra wire will not be a ground but it is probably related to the dial light. Originally there were two poles or switches to the volume control. One switched the power to the radio and the other switched the power to the dial light. These switches tended to fail over time and the replacement units only had one pole. Thus they would usually hook both the radio power feed and the dial light together on the new replacement switch. Some repair persons ( politically correct multi gender terms!) would bring the dial light feed out directly without being switched. Your extra wire may be attached to the dial light and the light may be burned out.

Extra Hole: there is no spot for an electrical probe. However, there are various holes in these radios which don't seem to have a purpose.

Thank you for the additional information.
The second elec connection is the dial light and it is operational.
I have removed the vibrator and powered the radio and I can see the heating element glowing in one glass tube, the balance of the tubes are metal. When I replace the vibrator and power on, I get nothing. The tube does not light. Absolutely no sound with antenna attached.
This radio was restored at one time and converted to 12 volt. I believe the transformer has been changed and the vibrator is solid state.
It looks as though the probe on the radio is for an external speaker. There is also an additional external wire connection to the on-off switch that is labeled 12 V SPEAKER.
I don't understand why I lose the heater on the tube with vibrator installed and why I have absolutely no sound ?

Rusty,
I assume that you are powering it from a limited source, like a trickle charger? If so, the vibrator or something downstream is shorting and the charger is probably at the max or tripping off on overload. Those solid state vibrators must be powered with the correct polarity or they will not work and probably will get damaged. If you remove the OZ4 tube, which is the rectifier, and you get the same result, it is very likely the vibrator is shot. If on the other hand the tube, which I think would be the 6V6 lights up, then the problem is further downstream than the vibrator. If you want to try that test, I would be interested in the results.

I'm using a variable output regulated power supply. It has voltage and amperage meters.
Your comment about the correct polarity made me check my connections and I'm embarassed to say I had my positive and negative connections at my power supply reversed. When hooked up properly, the 12V6 lights with both the vibrator and the OZ4 installed and the radio now plays. Thank you very much.
The volumn is very low with a car antenna hooked up. Do you think I've damaged some component ?
The voltage drops on my power supply when I put a load on it. I normally readjust to required voltage. Any problem with that ?

Rusty,
here are a couple of things to try, initially. By the way, it sounds like you have a nice lab supply that you are using.

First, is the volume low for all areas of the band? Second, have you tried all three positions of the tone knob. Maybe one position is faulty. Third, there is a small trimmer capacitor, which can be adjusted from the outside. It is located just under the antenna. See if that makes a difference. That capacitor is supposed to help match your antenna to the radio.

The position of the tone knob, adjusting the trim capacitor and a better connection to the antenna, brought the sound up to a comfortable level. It's working fine. I'm sure once it's connected in the truck and I'm out of the low area where I live, it will operate perfectly.
Thanks very much for your guidance. I appreciate it very much. Regards

Your radio may have a lited panel. The other wire may be to the lamp inside and hooks to the headlamp switch or panel lamp resistor.
If the buttons don't move the needle and the knob does the they may all be set to the same channel. Move the needle with the knob and pull out on the button you want to set for that new channel, then push it back in to set it. Will the buttons now move the needle?
Or yea what truckernix said. I guess I should read all the posts first. Then type my 2 cents.