1965 radio problem

[Steve Hess]

The radio was replaced in my '65 coupe by a previous owner with a am/fm cassette Custom Autosound brand from Ecklers. I don't prefer this unit and just wanted to replace the original back into the car. I was told it worked when it came out.
So I removed the am/fm cassette and plugged in the original to test before installing. I get power, I get a power on "pop" thru the speaker. I can hear a very faint radio station with the volume turned up all the way. AM stations are non existent, just static. I've searched thru much of the archive and still have the following questions.

Can running that non-original radio ruin the impedence transformer on the speaker?
Are there simple things to r&r an oem radio that will improve its function after 35 years of aging. Contacts to clean, tuner to lube, etc?
Is it possible to bench test the radio out of the car with a non oem speaker to tell if it is the radio or not?

Steve

[Jack H.]

Re: 1965 radio problem

Odds are good that when the replacement radio went in the original speaker with impedance matching Xformer went out.... If you run original radio for any length of time ESPECIALLY at high vol to compensate for loss of volume with ordinary speaker, you can kiss your DS-501 drive xsistor bye bye.

Back to your questions. Is is possible to bench test factory original radio? Lord, yes! How do you think current United Delco centers that work on radios do the work? I assure you they aren't taking their oscilloscope into the car....

You need a power supply (with Wonderbar you need a BIG power supply or battery due to 'spikes' associated with seek solenoid(s) operating), an antenna and a CORRECT speaker. The correct speaker may be the original, a repro with the xformer on it, or an aftermarket with the impedance matching xformer bridging the 'gap' between the radio chassis and the ordinary speaker.

Without the xformer, you're going to get extremely low volume, a very tinny sound and you run the risk of blowing the DS-501 driver xsistor. Also, prior threads in the archieves suggest using a replacement antenna to fault isolate between radio and your car's antenna lead-in. With an open circuit antenna, you can expect reasonable/good FM reception and virtually NO reception on AM.

[steve hess]

Re: 1965 radio problem

Today I talked to the person that replaced the radio. He said that the oem radio worked, but the volume was real low. So it appears from your description that the DS-501 drive transistor is going, going, gone? And/or the speaker transformer. Is it possible for a novice to test, secure and replace the DS-501 drive transistor. Likewise with the speaker transformer?