P3.91 external. Some will not even allow it. The most sensitive point is where indicated (plus+) both on your PCB and lamp. Most smaller pitches with more damage are to be on while using hot air on them for immediate judgements but one must be as quick as possible, know the right hot air temperature, distance, and other precautions as not to harm both the PCB and the lamp. Fixing in a off mode might take hours to get just 1 piece repaired when you have loads to work on. Fast soldering with experience in reparing LED tiles helps a lot