The Stovebolt Site Forums The Shop Area The Electrical Bay The Radio Bench radio noise

I've got a 62 chevrolet truck with the basic am radio. It had not been turned on since 1981. I opened it up, cleaned out the dirt dobber nests, cleaned it up and turned it on. It works! I have had the original speaker reconed, bought a repro antenna, installed all in the truck and it sounds fine but I've got noise, either ignition or generator. The caps check O.K. with a voltmeter, but still could be bad. Are these generic from year to year? Could I have another problem in the radio? The only glitch in the radio is it may not be as loud as it could be. Thanks.

Hi,First I would check the ground at the antenna base.It has to be clean and tight.Run an extra body ground GM part # 6286800 to frame.Then I would unplug the alternator and see if it goes away.From your GM dealer use noise suppresssion kits
part # 1224205 for alternator whine(battery line filter)
part #549216 for alt whine(installs at fuse block)
Part # 528172 for Heater blower whine
part # 3861562 for turn signal click
I have made a "sniffer" using an old antenna in severe cases.As for the low volume,the control could be foggy.Let us know how you make out or send me a PM.

Are you using resistor spark plugs? If not, that might be the problem.

Does the radio have tubes, transistors, or both?

Thanks for the responses. The radio is all tubes and I have the factory ground straps from engine to cab and cab to frame, though I still lack one from the radiator support to frame. the antenna is new and I'm pretty sure the ground is good, but I'll recheck it. I don't have an alternator, I guess those parts mentioned would apply to a generator equipped truck as well? The noise it makes does have a whine to it, but does have some ignition noise as well. By the way, what is a foggy control? Thanks, Bill.

Hey tan62,A foggy control is when "stuff" gets in the volume control and makes it so you don't have full volume or it's scratchy when turned.Radio Shack makes a spray cleaner on a nozzle that works well.Just pull the knobs off and spray some in the control.

Just a note here about noise. Your radio has an automatic gain control which varies the gain or amplification factor inside the radio, to match the signal strength. What this means is that if the radio signal is very weak coming in to the radio, the gain will be boosted and the radio signal will be boosted also. In addition, the noise will be greatly amplified. So, one of the important things is to make sure that the antenna is working properly.

Volume Control: When they have had a lot of use, there is wear that occurs inside the control. The outer finish on the wiper is worn off and the metal underneath oxidizes easily. Also, some of this metal finish and the carbon on the resistor surface becomes a residue and causes problems, which are generally described as a "dirty control". Usually once this happens, the contact cleaner is very helpful but the affect wears off fairly quickly. So, sometimes it is a matter of spraying it once in a while to keep it working properly.