I loaned my light, I know never loan grow gear..Got it back with 25% of the lights not working. Contacted Mars for instructions on repair as I bought it 11/2014 and warranty has expired. So I got a link to figure whats wrong. Well turns out a driver is bad but no matter what I did I couldn't get it to light. Switching drivers etc. Well after 3 rounds of disassembly/reassembly it came on 100%...Don't know why but I'm happy.