Hi there, I recently bought a Pioneer KP-77G which is not working (motor does not run, electricity is fine).
While searching for info about that device, I found your thread.
I looked several times closely to the video but could not figure out where you actually installed the AUX.
I found the left and right channel on my 77, but only direct output to the amplifier, i.e. treble, volume, bass have no effect.
Here is a picture of my 77: http://s23.postimg.cc/vbig4q8zv/IMG_20151024_212258.jpg
Do you have any photos of your hack? Or any idea where the left, right audio is on my 77?
Thanks for any help!