Radio

[Dan L.]

Found these two radio components under the dash. Its a 1970 with AM/FM Stereo. Assembly manual shows only the larger unit with AM/FM stereo and only the smaller unit with AM/FM. I'm a bit confused, been told I need both.

[Alan S.]

Re: Radio

Hi Dan,
The 71 AIM shows just 1 "adapter asm" for the stereo radio. It's shown in the location that your larger unit is. Perhaps someone else will pipe up to verify your 70 is the same.
Regards,
Alan

[Michael G.]

Re: Radio

Dan,
About a week or two ago someone (I think it was John Hinkley) went into depth about these units associated with the radio. You might check into some of the previous posts for the full story. Mike

[Dan L.]

Re: Radio

Dan,
About a week or two ago someone (I think it was John Hinkley) went into depth about these units associated with the radio. You might check into some of the previous posts for the full story. Mike

I did a search, Mike, must have missed it. I'll look again, Thanks.
Alan, thanks.

[Jerry R.]

Re: Radio

The larger unit is the stereo multiplex decoder for the radio and also contains the audio power amplifier for one stereo channel. The round black plug on its cord connects to the back of the radio. The smaller unit (often called a convector) is the power amplifier transistor (only) for the second stereo channel and plugs into the radio connector with the blue, green and yellow wires. I know the inner workings of the devices if you have any technical questions. And don't pitch them. They're rather valuable.

Jerry

[Tom L.]

Re: Radio

I realize that there are suttle differences from year to year in terms of vehicle construction but I was wondering if the brace in the posted picture going from top right to lower left is standard in early '70's C3's. Mine doesn't have one and am wondering if something is missing.

[Dan L.]

Re: Radio

Thanks Jerry, the assembly manual only shows the larger of the two, guess sometimes even that is not correct all the time.........

[Dan L.]

Re: Radio

I realize that there are suttle differences from year to year in terms of vehicle construction but I was wondering if the brace in the posted picture going from top right to lower left is standard in early '70's C3's. Mine doesn't have one and am wondering if something is missing.

Lynn, look to see if you have the studs the brace attaches too, the heater box also has a indent for clearence. Also there is another brace below the heater box which you can barely see in the photo.

[Richard R.]

Re: Radio

If i'm not mistaken the brace shown in the photo is only on the convertible. I own 2 and both have this brace.

[Jack H.]

Re: Radio

Your confusion lies in the way GM built the options. You start with U69 and make the added changes shown in the U79 section to achieve AM/FM Stereo.

If I remember correctly, the under-dash bracing changed when you had an A/C equipped car that was a convertible (beef up cockpit rigidity). That may be the other confusion factor as to why some cars have the brace and others don't...

[Richard R.]

Re: Radio

That is probably correct Jack. Both of my cars are air and convertible cars. One is a base motor and the other is a LS-5.

[Robert M.]

Re: Radio

The bracing is for the A/C Convertibles, to stiffen the cowl
Now having said that, I've seen a 69 non A/C car that had those braces, and read in the Restorer I think, years ago, that all 68 convertibles had the special bracing shown in the photos.

I'll try to find the article.