The Stovebolt Site Forums The Shop Area The Electrical Bay The Radio Bench Radio Restoration Help-- No sounds

Hello,

I am in the process of trying to bring a radio back to life in a 1949 truck but I can not get it to produce any sound. The radio is a Delco 986067. I bought the radio on line and have no idea of its history. All of the components inside appeared to be original with the exception of the vibrator which says "replacement vibrator" on it. Below is the steps I have taken.

1) Read the tech tip pages and searched for information
2) Replaced all of the capacitors and resistors (including the 0.006 micro farad 1600 Volt buffer capacitor)
3) Removed the original damaged speaker
4) Installed a modern speaker with two wires to hook up. (There were three wires going into the original speaker. One appeared to go to the output transformer, one to ground, and one to 6V power. The new speaker had 3 ohms resistance across the two wires. When installing the new speaker I hooked one wire to the wire coming from the output transformer and the other wire to the ground wire.
5) Removed the Vibrator
6)Powered the input lead with 6 volts and grounded the chassis using a trickle charger.
7)All of the tubes felt warm like they were heating up
8)Removed power
9)Installed the Vibrator
10) Powered the radio again

When I repowered the radio, I think I heard a very brief sound from the speaker (not positive). I could hear the vibrator humming for about 5 seconds or so. The heaters got warm. Then the vibrator quit humming. I do not hear anything at all from the speakers. The vibrator doesnt appear to be making any sounds. I rechecked the buffer capacitor and get 0.006 micro farad capacitance.

Any tips on where the problem is? Did I burn up the vibrator somehow? Was it just old so it only worked for a very short time or could I have damaged it some other way? Did I install the speaker correctly (Step 4)?

Any recommended sources for vibrators? Is there any specifications that I need to look for when buying one besides the number of prongs and the voltage it is for?

Any input is appreciated. Thanks