I tackled this problem with my SR Litage frame. Tried all the suggested methods along with a liberal amount of cussing and thoughts of sacrificing a virgin or chicken.
By happenstance, I had the cable stuck down the tube when I started twirling it back and forth between my finger and thumb. To my surprise, it popped out the back end. Tempting fate, I pulled it back out and repeated the process. After several successful repeats, I can only surmise that there is some type of ramp or funnel installed that helps thread the cable through.
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This is Africa, 1943. War spits out its violence overhead and the sandy graveyard swallows it up. Her name is King Nine, B-25, medium bomber, Twelfth Air Force. On a hot, still morning she took off from Tunisia to bomb the southern tip of Italy. An errant piece of flak tore a hole in a wing tank and, like a wounded bird, this is where she landed, not to return on this day, or any other day.