I found bring the OP-1 higher up off my work surface made installing the ribbons much easier, oh and keep the keyboard assembly parallel to the OP-1 to ensure the ribbons seat evenly.

I had a bad solder joint on the headphone socket. This guide helped me fix that. All working now. Thank you.

I used the same scalpel to very gently lever up the board from the top right edge, there was a sound of adhesive being pulled from, same at the bottom. Then used tweezers to tease out the board by the headphone jack. The reason for doing this was the right side audio only worked when pushed the jack cable away from the body. I suspected a bad solder joint and so reflowed all the 6 legs. It worked.

I used a broad edged scalpel to do the same thing, just popped right out.