Variable talk back install in older 148-GTL side-mic

[kc5mbs]

I have an older Taiwan-made Cobra 148-GTL. I just got my UTB-1 variable talk back kit. The instructions apparently only apply to newer radios. They require cutting a board trace at the external speaker jack and soldering a wire to each side of the cut. The problem is my old radio has no such trace. I am hoping to find someone who has performed this install on a 148 or Grant-XL. Any input would be greatly appreciated.