Any info on adding an aux. input to vintage radio?

[CandyAppleRed 10]

Spent some time figuring out a plan of action here. How does this sound:

 

Right Channel

Desolder capacitor at point 121 ( + end ) and pull it's lead out of circuit board.

Solder wire from right channel common on switch to capacitor lead just pulled from circuit board.

Solder wire from right channel radio side of switch into hole capacitor lead was in.

This puts the right channel radio switch in between the capacitor and resistor R314.

 

Left Channel

Desolder and pull out resistor R313 lead at point 110 on board.

Solder wire from left channel common on switch into hole R313 lead was in.

Solder wire from left channel radio side of switch to R313 lead pulled from board.

This puts left channel radio switch between capacitor and resistor R313.

 

I think there's enough room to pull it off that way. I will do what it takes to get the 6.8K resistors. I don't think the 100 ohm will be a problem. So where do the 6.8K resistors go?

[danno 128]

Your method will work, and you will not need the 6800 ohm resistors. The reason you might have needed them is because sometimes when I do it, it is easier to clip the resistor in the middle, breaking it in two. Then I have 2 places to solder the new wires.

 

Your method of doing it will work perfect, and you will not need the resistors. You still should get the 100 ohm resistors for the MP3 output.

 

So do it by your method and it should work fine.

[CandyAppleRed 10]

Awesome. I may give it a try tonight if I get time. The weekend is pretty packed.

[CandyAppleRed 10]

Success! I now have an aux. input for my vintage Ford radio. It's been a long time since I've smelled rosin core solder melting. I may have to get another subscription to Popular Electronics Magazine!

 

 

 

Below is the area of the circuit board where the connections were made.

You can see capacitor C313 is missing. It was pulled to allow a bit more room to unsolder one end of resistor R313. A wire was soldered to the now exposed end of that resistor and another into the hole the resistor was pulled from. One end of capacitor C313 had a wire soldered to it while it was out. Another wire was soldered into the + hole for the capacitor. The negative end of the capacitor was then resoldered into the appropriate hole. Heating the holes to melt any remaining solder, then giving them a blast from a can of Dust Off opens the holes up nicely to reinsert and solder connections as necessary.

 

 

 

I ran the wires for both channels out the same place in the case that the positive power lead enters it. It didn't dawn on me until I was taking this photo that placing the wires there could induce noise into the speakers. It didn't seem to during a short bench test. But I may move them anyway. The white wire mounted to the wire clamp screw is a ground for the aux. input socket.

 

 

 

I placed a 4 pin jack plug in the wires between the radio and the radio/aux. switch to reduce clutter while installing the radio. I'm not even sure yet where the switch and socket will end up. My 69 Mach 1 is still about a year from completion. The single white wire is the ground for the input jack.

 

 

 

And finally at the end of the line, the radio/aux. switch and the auxiliary input jack.

 

 

 

A HUGE Thank You to danno for his generosity in providing the information needed to pull this off.

You rock dude!

 

 

.

[69gmachine 15]

Well, I'm certainly inspired to attempt it. My radio looks very similar to CandyApples, but I still can't figure out why splicing into the 8 track inputs didn't work. If I can figure that one out, I won't have to add a switch. Any thoughts?

 

I suppose it's not that big of a deal if I have to add one though. I could hide it in the console.

[danno 128]

Great job, I know the felling of sucess when you actually see an accomplishment like this. I must admit, I was not sure about those 100 ohm resistors added in the audio line, but it sounds as if they worked fine. It looks like your work is very high quality, with nice solder joints, connections, bundles, etc.

 

I usually do it a bit different in that I use a relay inside the radio to do the switching. Then all I need to do is run a single wire to +12 volts at a switch to do the changeover. The other thing I always do when I make the mod is add a USB cable to supply power to the mp3 player. That way it is always charged. I just got through doing a mod to another AM/FM that will be going onto Ebay this week, I will reply when I do so you can see what I did to accomplish the task.

 

For 69gmachine, somewhere inside your tape player/radio is a switch that changes the audio from tape to radio. You can usually connect your mp3 to the audio output of the tape player and disconnect the tape player audio output at this switch. If you do this, you still need to slide in a tape to engauge the siwtch to change from radio to tape.

 

I just finished doing the mod for a person in International Falls, MN. That is just down the road from Frostbite Falls, where Rocky and Bullwinkle were from. Anyway, I did the mod in a AM/8 track player from a 68 Fairlane, and it was not that difficult. So if anyone else wants it done, I can do it for them. I can also answer questions if anyone wants to do it on their own.

[CandyAppleRed 10]

Thanks for the comments danno. I used to do projects out of Popular Electronics many, many years ago so I wasn't starting completely from scratch.

 

I originally hoped that I could fit a micro switch and the jack somewhere right on the face of the radio. But things are so packed in there that wasn't happening. Now that I've done it and it works, I wouldn't hesitate to chop it up and add a relay as you do. The main thing is that I now know where to make the connections, thanks to you.

 

My car is a completely empty shell right now so I'm not sure where the switch and jack are going to end up. Right now I'm expecting to put them in the ash tray pod at the bottom of the dash. Possibly inside the ash tray itself. If they end up someplace further from the radio I'll likely go the relay route to reduce bulk.

 

Thanks again danno! And best of luck with the auction.

[69gmachine 15]

For 69gmachine, somewhere inside your tape player/radio is a switch that changes the audio from tape to radio. You can usually connect your mp3 to the audio output of the tape player and disconnect the tape player audio output at this switch. If you do this, you still need to slide in a tape to engauge the siwtch to change from radio to tape.

 

I found the switch no problem, and I intended to use an old 8 track (bought several for something crazy like 25 cents apiece) to switch on the ipod and give the illusion that I was playing a tape. The 8 track head has left and right channels with individual grounds that tie together inside the radio chassis. On the radio side the wires have sockets so they just slid right off and I discarded the head. I haven't been able to find pins that small, but then I haven't tried all that hard. I have hundreds of 22 ga. pins but they were all too big. I've been focusing on getting the car back on the road lately (and in fact had a very nice shake down drive last evening).

[danno 128]

What is the part number on your radio? I will see if I can find a schematic on it. This is the same process I went through with candyapplered, to start with the paperwork. That will tell me a lot about what you have and are working with. The model number should be something like D2AA-12H223.