Older panels had serviceable junction boxes and diodes, but unfortunately modern split-cell panels have fully sealed junction boxes which makes it extremely difficult to replace a blown diode.
I recently came across a system that had 3 panels with blown diodes due to a reverse current after the installer accidentally connected the system with reverse polarity. I’ve never fixed a modern split-cell panel with blown diodes so here is how I did it. Interested to know others’ experience trying to fix blown diodes.
Steps to fix blown diodes:
- Remove plastic covers
- Use a sharp blade to cut a rectangular area around the diode
- Use a very fine flat head screw driver to pick out the filler material
- Scrape away as much filler material as possible from around the diode
- Heat the solder and remove the faulty diode (test diode first)
- Solder the new diode in position - I used new 30A diodes 30SQ030
- Fill with fire rated silicon
- Replace the plastic cover and cover it with more fire rated silicon
Remember to test the new diode before adding the silicon filler.