Soldering underneath chips

Step 3 File back the topside

Now comes the delicate part.

Carefully file as much as possible without scratching surrounding trackwork. Take your time here....it is very difficult and cannot be rushed.

When it gets too close to file, use a scalple blade to scrape away even more. The copper and the solder should be reasonably soft.

In the first picture you should be able to see the cores of the copper wires that were poked through starting to appear.