1966 Rear seat speaker Problem

[old timer]

I have a 66 Bird and putting in a rear speaker I have a problem. The radio is an AMFM model for my 66. It has a fader but when I plug in the wire in the rear myh fader doesn't tranfer the sound to the rear. Has anyone had this problem and what do I need to change?

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[Gary Tayman]

First thing: is this the ORIGINAL RADIO for the car? I ask this for good reason. There were two ways of wiring the fader controls for these Birds, and I can tel you, Lincolns did the same darned thing. How just a couple wires can make for such a confusing mess is unbelievable, but they've done it.

Speaker wiring number one: This was used on all 64 radios, and 65 AM/FM. I'm not 100% certain if they offered a fader-type AM radio for 65, but I can tell you the 65 and 66 AM radios are the same model. The plug has one male pin and three femake pins. The male pin is ground, and the pin next to it is radio output. So if you have a single dash speaker with a 2 pin connector, plug it in and it will work, and the fader control does nothing. The next twp ins go to either ned of the fader control, with the wiper of that control grounded. With a 2 speaker system, forget the ground pin. The output pin goes to both speakers. the negative side of each speaker goes to the two other pins, si that either speaker has resistance to ground, allowing adjustment.

With me so far?

On the 66 AM/FM it's done differently. Yes indeed. The connector is the same, the first two pins are the same, but the other two are different. It is a convoluted confusing arrangement where the fader control is grounded on one end, and the wiper adjusts the midpoint between the two speakers. I've got an illustration around here somewhere, but let's just say it's confusing and incompatible. If you connect the wrong radio to the wrong car, the fader won't work properly.

Did the 66 have one wiring harmess for an AM fader set, or did it exist at all, and another wiring harness for an AM/FM set? I can't tell you. But maybe the first thing to do here is check the radio to make sure you have the right set. The 65 is model TOB5TBS, and has a single power transistor on the right side of the set. The 66 is a TOB6TBS and has two power transistors on the right side. If you're putting a 65 radio in a 66 car, the fader will not work properly.

 

[old timer]

To check model where is the model no. Do I need to pull the radio out to see. It is a 66 radio I was told. The plug in for the speaker is black and red. The fader when turned lowers the volume down on the front speeker.

 

[Gary Tayman]

The 1965 and 66 radios look identical in the dash, but are different internally. If you look at the radio, the top, bottom, back, and left side are sheet steel but the right side is aluminum, as a heat spreader, and usually (not always) painted black. The audio output transistor(s) are mounted on the heat spreader and covered with a piece of fish paper. The 65 has only one transistor, and has "TOB5TBS" stamped into the metal above it. The 66 has two transistors and has the number "TOB6TBS." I guess the 65 has a single-ended audio output and the 66 has a push-pull output. I don't know what difference it makes; either one only offers 3 watts divided between two speakers, or 11/2 watts per speaker.

 

[old timer]

Thanks for your help, looks like I need to take the center console apart again. I plan on checking to see if I have current to the rear speaker first.

 

[Gary Tayman]

On that note, there is a way to check without tearing out your seats. Take a couple of clip leads, or just pieces of wire, and a battery.

Unplug the four-pin speaker plug from the radio. Yes, this means taking off the console side panel. While you have that panel off, maybe you can look inside at the radio to see if it has one or two power transistors. But then, grab that four-pin connector (to the car, not the radio). The single pin is ground -- forget that. the pin next to it is radio output. With a battery, (AA, C, or D but actually a 9v works best) use the wires to touch one side of the battery to that second pin. Touch the other side to one of the other pins. Then try the last pin. As you touch the battery between these pins, at some point you will hear a crackle from the front speaker and at some point you'll hear a crackle from the back speaker. If the speakers make noise, you have continuity.;

 

[old timer]

I do not have voltage coming from rear wire The radio is stamped Jan 1966. I removed the right side panel and found the stamp.

 

[old timer]

I just checked my AM radio and it has a fader. Shouldn't be the same connector?