Originally posted by mockingbird812:
My radio is an original radio for a 69. I don't know its history or functional status. It is an AM push button radio with a singel dash speaker (10 ohm). Two plugs go into the back receptacle of the radio (just like in the assembly manual-RPO U63). The power plug (small) plugs into the speaker plug which then plugs into the back of the radio. I am getting 11.9 volts thru the power plug when the key is turned to ACCESSORY. But, when I turn the radio to the ON position I get no light or any sound - not even static.
BTW, the antenna is hooked up too.
Is there a way to test my radio for functionality (considering my somewhat limited electrical skills)?
Any thots?
Thanks,
Sam
Hello Sam,
Probably a moot point by now, but for future reference, you never want to "crank up the volume" if you are under suspicion that the radio does not function. 99% of the time the speaker is shot, sunlight and heat and time play havoc, and the voice coil goes open. When the radio no longer "sees" a speaker, 2 things happen, first is obvious, no sound. The 2nd thing, which is human nature is to continue to turn the volume knob in an attempt to hear something, this is not a good thing to do on any vintage Delco. The output ciruitry is arranged so the power output transistor drive the output transformer, when there is no load (no speaker) a very large induced voltage is created in the output transfomer, this in turn exceeds the collector-emitter break-down voltage of the transistor and thereby either ruins it, or shortens its life dramatically. These output transistors were not the best to begin with (germanium-based, heavily circuit-biased and always run hot). They are now obsolete and hard to find, making it important to use care and caution when testing this era of equipment. Just an FYI. Don't feel bad, everyone does the same thing. Just do NOT try anymore without seeking a qualified bench technician.
Joe
