AUX input jack for 67-72 AM radio

[69-72]

Originally Posted by BBrendal

Sweet!

Originally Posted by chuck69ss

Couple of thoughts:
1. A cap soldered to the case sounds like a tone control, rather than volume. These are stacked pots, right?
2. The easiest way to figure this out is with an oscilloscope. I have also used a set of headphones with one side tied to gnd and uses the signal lead to poke around and follow the signal path. You want to find the input side of the volume control.
3. I wish that had an AM/FM to figure this out. :-)

Maybe someone else has figured this out.

So I did the headphone thing. I found sound when I probed the blue wires on the circuit board, only problem is afterwards when I hook up my aux source to them it does go through but is very faint. There are also two different points on the board that the blues go to, one of them has two blues going to it, only one of them the source is heard over, the other point also plays the source when it is applied.



Edit: I discovered that when the source is hooked up to the blue wires it is not being amplified, volume stays at same level when power is removed from radio