Sorry to hear.. I did that to my cobra 29 and if I remember correctly on it I soldered one leg of a 60 ohm resistor on my pa terminal and the other to external speaker terminal. I didn’t have the variable added, but I think you could add a potentiometer between that connection or use an existing one ,if you have one that u don’t use on your radio. I think they recommend a 100 ohm, but to me I didn’t think a 100 ohm was loud enough , so I went with a 60. You probably could purchase a a variable knob online and put it in somewhere that u have some room for it and solder it between your ext speaker and and pa. Hope that is some help