Solar Builder has created a field tech’s guide to inverter troubleshooting. They recommend documenting every step once you get on site and gathering background info on all components. They also say to carefully review your solution with a colleague, make lists re tools and have a clear safety plan. The guide includes a list of about 15 tools to have on hand and details info on documenting, checking peripheral connections, and measuring when on site. SB also recommends taking photographs during stages of the assessment and repair. Check out the details here.