67 AM radio band not working

[Bill K.]

Searched the archives and didn't see anything ...

When radio is installed in car am band only has static. FM works fine. Had radio checked on a bench and both bands work. Obviously this points to the antenna. Looking for advise on where to look before I just replace everything. Any measurements I can take to determine if it's the cable, the antenna base etc ?

Thanks !

[William F.]

Re: 67 AM radio band not working

Maybe no AM stations. Lol but not many still around.

[Don H.]

Re: 67 AM radio band not working

It does sound like the antenna. Did it work before the radio came out? I would use whatever you used on the bench for antenna (you said it worked on the bench). If that works, cable or antenna? Getting to the antenna can be fun. The easiest way is without the muffler but that is not easy either. Removing the spare tire tub helps a little. You could check the cable with a volt ohm meter. Good luck, Don H.

[Ed S.]

Re: 67 AM radio band not working

Bill,
Before you begin pulling things apart, have you adjusted the antenna gain screw on the side of the radio? If no, I recommend you do that first - there is a small screw on the right side of the radio that you can adjust to tune the radio to your antenna. You have to remove the passenger vent cover to get to the screw. Also, I recommend that you make this adjustment with the car parked outside - away from any neon lights that might be on (like in a garage) as they will cause static. If you need more info on "how to" adjust the antenna gain screw please speak up - I think there are a few threads on this subject that I can help you find.

[Timothy B.]

Re: 67 AM radio band not working

Ed,

Can you explain better the adjustment, is there a dial setting that is weakest that the sound is tuned too.

Thanks for posting that..

[Ed S.]

Re: 67 AM radio band not working

Timothy

I am quoting Jerry Rudbeck of Electro Design - he is an expert C2 radio repairer / technician. I sent my '64 radio to him for a refurbishment and he did a fantastic job. When he sent the radio back to me he included some instructions. The following pertains to the AM antenna gain adjustment.

"Adjust the recessed antenna trimmer screw on the case side rear near the antenna jack for maximum loudness on a very weak signal near 1600 on the AM dial. If the trimmer does not "peak" the loudness within its range of travel, an antenna or feedline problem is indicated."



I hope this answers your questions.

[Bill K.]

Re: 67 AM radio band not working

Thanks for the ideas. Actually had a friend test the radio on the bench and I trust him that it worked. To answer the questions, no, AM did not work, that's why I removed the radio. Not a fun thing to do just for the heck of it ! I did back the car out of the garage to verify function after it worked on the bench so should have been away from any interference. I'll see what I can find on gain adjustment and see if that helps. As far as ohming out the cable, does anyone know "correct" readings ? Is there any component in the antenna/cable that is AM unique ? I know old home stereo's had separate am/fm antenna inputs. Good news is it's a side pipe car so access shouldn't be too bad.

[Bob R.]

Re: 67 AM radio band not working

If you live far from the broadcast signal reception is generally poor. Make sure you have the antenna all of the way up when testing for am signal.

[Ed S.]

Re: 67 AM radio band not working

Thanks for the ideas. Actually had a friend test the radio on the bench and I trust him that it worked. To answer the questions, no, AM did not work, that's why I removed the radio. Not a fun thing to do just for the heck of it ! I did back the car out of the garage to verify function after it worked on the bench so should have been away from any interference. I'll see what I can find on gain adjustment and see if that helps. As far as ohming out the cable, does anyone know "correct" readings ? Is there any component in the antenna/cable that is AM unique ? I know old home stereo's had separate am/fm antenna inputs. Good news is it's a side pipe car so access shouldn't be too bad.

Bill -- just to be clear, even though your radio worked on your friends bench you should still try to do the adjustment thing when it is in the car - the antenna your friend used may be different than the one in your car. Also.... if you find that you need to replace the cable do some research - as I recall, according to C2 radio experts there are few antenna cables available on the market that are the correct impedance.

Here is a cut and paste from Jerry Rudbeck's webpage (http://electrodesign.us/index.htm) re C1 & C2 antenna cables - hope this is helpful to you.

Why is there a problem with the antenna cables the vendors are supplying for the 58-67 Corvettes?

[Timothy B.]

Re: 67 AM radio band not working

ED,

Thanks for posting that information, I will have to give it a try on my 67 radio.

[Frank D.]

Re: 67 AM radio band not working

The ohms are impedance you aren't gonna measure them with a multimeter -- there is a radio ground w-a-y up at the antenna base - critical on a fiberglass car as it connects to the chassis to provide the antenna 'ground plane'. FM may well work and AM will be poor to non-existent if the ground is missing or not attaching well...

[Joe R.]

Re: 67 AM radio band not working

I had this same problem when I bought my '67. Turned out that the antenna cable was not connected back at the antenna base on the rear fender. Surprisingly, FM still worked okay but AM was just static.

[Daniel Y.]

Re: 67 AM radio band not working

Bill,

I'm sure I'm stating the obvious but AM reception is terrible now a days. Most radio stations have not maintained there equipment. I live in an area in PA mountains that depending on where I am the reception goes from pure static to fairly decent reception.

Having said that MOST of the repro cables are thin and terrible and easy to break the cable. If you can find an original - buy it. if not, buy a few of the repros but before fishing it through the car run it to the antenna and see it makes a difference if it does install if it doesn't return to LI or Paragon or CC. I have found a few of the repros that work. it just takes a little time finding the one that does

[Bill K.]

Re: 67 AM radio band not working

Thanks everyone. I did take a quick look yesterday and the antenna cable appears to be seated properly. There is a ground, appeared to be more of a wide/flat copper colored strip coming from the antenna base down to the frame. Connections could use some cleaning. Didn't have time to play with it this weekend but will when I get back at the end of the week. So will take it all apart, clean and reassemble and see what happens

[Jimmy P.]

Re: 67 AM radio band not working

Bill,
I had a similar problem with my 73 am/fm radio. My FM worked fine but my am just made a high pitched squeal. So I sent it out to Jerry Rudbeck for repairs. He's the best! He replaced some worn out parts, and replaced my dial numbers, and cleaned everything. He bench tested it before returning it to me. When I installed it I followed his adjustment instructions as mentioned in a reply above. My FM worked fine, but the am was only static like yours. I talked with Jerry and he said it was fine when he tested it, he suggested cleaning my antenna end and spreading the spring like things on the plug to make it fit tighter. I tried this, but still static. Then, to my surprise I started to move the antenna cable plug end around a little, and pulled it about halfway out of the radio and the am came in perfect. So I managed to get the plug end to stay in that particular spot and it has worked fine ever since. I 've driven the car many times and it's been fine. I told Jerry what it was doing and he was very willing to look at it again to see if there was an issue in the radio where the antenna cable plugs in. But, I did not want to go through the difficult job of removing the radio. I'm satisfied, it's working fine. Just another option for you to try before you take out the radio.
Good luck! Let me know if you get it working!
Jimmy