1970 Radio

[Joe W.]

Hello,

I'm curious to know the best way to find out if my radio still actually works.
When I got the car last July, I turned the key to accessory and also with it
started (barely) I turned the knob on and nothing.

So I looked at the fuse, it was still good. It has what appears to be
red lines in it. Nearly all the fuses have these red lines in them. Anyway,
I can see the speaker in the dash pad from looking up from beneath the
dash.

However, I'm not sure if it's connected or not. Would the speaker need to be
connected in order for the radio to illuminate? What is the best approach for
determining if the radio does in fact work?

Thanks.

[Jack H.]

Re: 1970 Radio

The radio's face plate illumination should be controlled by your headlight switch (lights up at night along with the rest of the instrument panel gauges).

The standard radio (AM/FM) came in TWO pieces: (1) the main chasis (center console), and (2) the convector unit (mounted behind the RH passenger dash).

This is unlike passenger car radios of the era that were one-piece in construction. The 'convector' is a fancy name for a simple heat sink with the DS-501 audio drive transistor mounted on it. This is what converts audio output voltage waveforms to current waveforms to drive the electro-magnets in the speakers.

Without the convector unit installed and working properly, you won't get any output. The cable interconnect is nicely shown in the U69 option section of your copy of the AIM...

[Jim T.]

Re: 1970 Radio

One check you can perform is to remove the forward conslole panel piece (one screw retains it) on the drivers side and verify that the wiring harness connector to the radio is still plugged into the radio. With the radio fuse already checked, you can upplug the connector and verify that you have 12 volts at the connector.
Since you can see the speakers from under the dash easily, you must not have factory air which helps in removing the radio. My 70 has air and I have not removed my radio since 1976. Anyway my 68 does not have air and removing the radio was easier than my 70. You can try just removing the retaining nuts behind the radio knobs, the wiring harness connector, metal brace, and the antenna cable, and see if you can work it forward and remove it from the passenger side.

[Joe W.]

Re: 1970 Radio

Thanks Gents.

Where behind the RH dash and what does this convector unit look like?

Thanks.

[Patrick H.]

Re: 1970 Radio

Joe,

It looks like this:

[Joe L.]

Re: 1970 Radio

Joe,

It looks like this:

Patrick------


In GM nomenclature, the unit on the left side of your photo is the "adapter" (used with stereo radio only); the unit on the right side is the "convector".

Now, I suppose one could say that the unit on the left shows a "convector" attached to some other electronic assembly which together constitutes the "adapter". Nevertheless, the unit, as a whole, is called an "adapter".

[Jack H.]

Re: 1970 Radio

Of course, there's a configuration difference between the standard AM/FM radio (convector only) and the optional AM/FM/Stereo system (introduces the converter)... Later versions of the Delco radio embraced greater levels of electronic integration allowing the converter to be eliminated and the convector changed to a dual channel, two DS-501 transistor assy. Here's pix of the later dual channel stereo convector and the early single channel convector...

[Alan S.]

Re: 1970 Radio

Pictures! Pictures! Pictures! I love it!!!!!!!
Regards,
Alan

[Joe W.]

Re: 1970 Radio

Hello,

I went to my barn, got up under the dash and using a flashlight and
my phone, took a couple of snap shots of my speaker and what I believe to
be the convector. Both appear to be in good condition.

Both connect to a wire harness to the radio.
Once I find a carburetor and buy a new battery and get her running,
what would be the next thing I look into to find out why the radio doesn't
work. The "redline" fuse in the fuse box is still good.

Thanks.

Joe