You need to access the circuit board connection feeding each string of LEDs If you cannot see the tracer lines connecting the LEDs, the process of fixing is impossible.
You also need to think about what you are going to do. Meaning if an entire string of lights meaning a row, is damaged, you need to cut either the positive or negative circuit board trace line (silver colored). Trace lines are silver in color. Silver OK? Got it?
To cut the trace line you need a sharp pointed object or best of all an exacto knife blade tip. Start scraping. A tiny canal scraped across the line is enough to chop power to that string. It's just like cutting a wire.
Measure twice and cut once.
Again, if the lamp circuit board is jammed packed and/or laminated like a sandwich making it confusing to the eye, then you might want to reconsider. Some of these circuit boards have a permanent cover (lamination) covering the circuit board. The lamination is heat sealed and impossible to remove without utter and total destruction.
EXAMPLE of a generic non led circuit board
Keep us posted :)
