General MG OEM Radio wiring help

I've acquired a British Leyland (Mororola) radio for my '79 Midget. The car had a radio installed by the dealer when new but that was removed by the original owner long ago...classically, he hung a cassette tape deck below the glove box and put 4 speakers in the car...2 in the foot panels up front and 2 in the boot. The cassette player was gone when I bought the car My intent is just to get an OEM type radio back in the console. I bought the car from the original owner in the early spring. It has 19,000 miles on it. He'd parked it in 1986 to save for retirement but found he just wasn't gonna get to it ever again. After going though a few things, I finally started it in June. With some carb adjustments it has been running great. It's not a concours car but it is in great condition and getting an OEM radio back in it will be a nice touch.

I've spent a bunch of time searching for a manual for this model radio...to no avail. The attached pics show the radio. I could use some help understanding the wiring.

The red wire appears to be the main power since it connects to the on/off knob. It would connect to the 12v behind the console with an inline fuse. I have a copy of the radio installation instructions the dealers used so can see how the power is wired.

What is unclear to me is how to connect the 2 black wires, the brown wire and the brown/yell wire. If this radio is set up for 2 speakers and I have a single speaker in the console, how do I address that?

Any insight is appreciated.

Update: The radio is reportedly from a '74 MGB with 2 speakers.

Mornin'!

You'll need to verify this with a VOM (volt ohm meter), but here's my recollection from waaaay back:

First off, are you sure the radio is designed for two speakers? Is there a switch for front/rear?

Then, red is power input (should have an inline fuse); brown is ground (check to make sure it's connected to the radio housing); two black wires are for the speaker (one should be ribbed/striped - that's for the positive speaker terminal). I think the yellow wire is for the internal light, wired to your light switch.

Hopefully, someone else will chime in as well.

And please keep us posted.


Mickey

I think this might help

http://www.spridgetguru.com/TA0037.html

and wiring

http://www.spridgetguru.com/TchIndx05_files/RadioPartsList.pdf

cool find!

Updated info- the radio is probably from a '74 MGB and had 2 speakers.

I uploaded another photo to the first post showing the radio chassis interior and where the wires seem to go.

The radio dial light is powered off the on/off knob. I don't think the radio is lighted until you turn it on....not dimmable nor connected to the dash lights.

Each of the 2 main knobs have a secondary function using a chrome ring knob behind it. I recall from my youth that some radios had a front/rear speaker balance built into one of these secondary knobs.

The multimeter shows zero resistance between the radio chassis and the wires, except for the red which goes to the on/off knob. That red wire to the knob shows no resistance when turned on. I suppose the whole system is grounded through the mounting strap on the back of the radio.

I have mine (AM-FM) grounded to the nut on the back of the case as shown in your pic #3.