For what it's worth, I just skimmed back through this thread and counted a total of six people reporting failures of their 990's that required a warranty repair. That's six over the course of over 3.5 years that the 990 has been in production and almost two years that the thread has existed. It's not something that any of us would like to encounter in our own equipment rack, but it's why that five year warranty is there and the numbers seen here suggest that your odds of needing to use that warranty are extremely low.