Hi,
I’m a newbie. Have a 72 I’m working on … original radio seems to power on (because I can tell the faceplate lights up when the headlights are on) and all the buttons seem to work, but no sound at all. Are speakers shot? Loose wire? Bad fuse? Just trying to get some sound. Wiring is all original and dash has never come out to my knowledge. Thanks!

 

Does the radio appear to have power with the headlights off? Not easy to diagnose this I understand. And with a car as old as ours it could be any number of things. THe first thing I would do is get a schematic of the wiring system in the car. I got mine and had the pages enlarged and laminated since I would be using them a lot. Then I would find the fuse for the radio and make sure it's not blown. You might be seeing the light that comes on with the dash lights which does not necessarily mean the radio is on. If the fuse is good you will have to open a can of worms, as in remove at least one of the speakers and the radio and then start testing. If you do a search there would be detailed instructions.
This could be something as simple as a bad ground, or a blown fuse or a bad radio. Then the real fun will start like what will you replace it with.....It is pretty common for any number of things to go wrong with these radios so you will have your work cut out for you. Make a plan and then follow thru each step, starting with the fuse. ANd as you start taking the sstem apart watch out for hard brittle pieces of wiring. THat will be the next decision you have to deal with, how brittle can the wire get before it becomes a fire hazard.
Or you could just put a bluetooth speaker in the back and play it thru your phone. Welcome to the world of old corvettes!

 

You don't hear any noise at all, like a thump or pop when you turn the radio on? More than likely corroded.

You can get a cheap auto speaker to test the output of the radio — one warning however: The original speakers are rated at 10 ohms but modern speakers are 4 ohms and will damage your radio if used for anything but a short term test. Remove the passenger map pocket panel and you'll have access to the right-hand speaker. This will also give you access to the speaker wiring harness from the back of the radio.

An alternative test is to use a 9v battery. Google for directions.

If your radio isn't working contact Robert Pacini - he fixed my '72's radio and is well-regarded here on the forum for restoring and fixing these old radios. (He can also bump output, add bluetooth, and stuff like that.)

 

Is the car new to you and radio doesn't work, or was it working recently and just went out?

 

I’ve had the car about 10 months and it’s never even made a pop from the speakers. I realized I don’t have the power antenna installed or hooked up - is this part of the issue? Where is a good place to buy a new one? Entire kit? Could this be a good place to start?

 

Without an antenna, you should still hear the speakers thump when the radio is powered on.

 

This is photo of a 1972 radio I found in another thread. Assuming yours still has the stock set up, there is a separate amplifier if you didn't know that already. The black thing on the left. Amplifier could be bad and radio good. Or radio bad and amplifier good. Or both bad.

If it lights up with the headlights, that might just be night lighting separate from the radio function. So, radio could be dead even though it lights up.

You asked if it could be a bad fuse. Sure could be, check it and let us know.

 

It is most likely the speakers in the dash. Mine were working fine, next spring, then no sound. It can be a pain to replace them, but as others have said they are 10ohm. Once I opened up the dash I found they had been replaced before, same 1972 coupe with stereo radio.

Joe

 

Mine didn't work so I pulled it out , bench tested it and it worked only with the amplifier connected , without the amplifier it doesn't work at all. So I found a bad connection on the amplifier hooked it up to some speakers and it worked great. Put it all back into the car and nothing , then I hooked up my other speakers from the bench to it and it worked, found out that the speakers are totally dead , factory speakers... Replace speakers and everything works great !

QUOTE=Pbpabs;1609318355]Hi,
I’m a newbie. Have a 72 I’m working on … original radio seems to power on (because I can tell the faceplate lights up when the headlights are on) and all the buttons seem to work, but no sound at all. Are speakers shot? Loose wire? Bad fuse? Just trying to get some sound. Wiring is all original and dash has never come out to my knowledge. Thanks![/QUOTE]

 

Agree w/ zxryder72 - the radio light is controlled separately by the dashlights. Yes, check your fuse.

72s didn't have power antennas AFAIK. But sure you can add one if you like. A length of unshielded wire will also work in place of antenna temporarily. Since you indicated this is a stereo and not a mono radio - you should have a stereo tuning light indicating lock as you spin the dial.

You can also switch to AM and see what static you can pick up too.

If everything is original I would say there is a high probability the original speakers are done and will need to be replaced.

 

Your radio, assuming its all original, likely needs all the capacitors replaced. Capacitors of the era were great at the time but after 5 decades they're likely shot. I would bet your speakers are still working and the radio is the source of your problem. The DS501 transistors in the amplifier of your radio were quite durable but sensitive to load. They need 10 ohm speakers. Modern 8 ohm speakers will work but will run the outputs on the hot side but not to the point of over heating unless you turn the volume up high all the time. 4 ohm speakers will cook the outputs. I bench tested this and its not an old wives tale. Modern 4 ohm speakers on a vintage Delco radio will smoke the transistors. Even 8 ohm speakers will eventually kill the output transistors. And they are impossible to find at this point. I digress.
Your vintage radio will likely need to be overhauled if you wish to keep it and have it a working radio. I am finishing the restoration of the factory AM/FM Stereo out of my 73 Coupe. I worked as an electrical engineer back in the 1980' so I figured I could handle this old radio no problem. Except I completely overlooked the parts availability problem that the year of our Lord 2025 comes with.
End of the day, probably better off finding someone that does vintage radio upgrade/rebuilds and let them sort it out for you. Just know, it isn't cheap.

 

Anyone have any experience in dealing with this radio repair guy?

www.joesclassiccarradio.com

 

This may sound crazy, but have you got the radio tuned to a known strong signal station? A buddy bought a 71 with an original am/fm and we thought the radio didnt work because like you, when it was turned on, nothing. When I tuned it to the strongest local station, sure enough, there it was. If I were you id make sure i had your antenna squared away.