I was curious if anybody has any failure history on the 300XL. The reason I?m asking is that I purchased a used unit (individual on Barnstormers) with an 8130 certificate and after installation the unit was working well (radio and GPS), but after less than 10 hours of use, while the radio was on and just being monitored, an audible pop was heard, the unit failed and a brief/faint acrid smell was present. I?ve checked the connectors (after removing the unit from the tray) and power is still present and the remaining pins indicate as expected as far as grounds. Whatever occurred seems to be in the unit itself. I am going to take it to our local avionics shop Monday and was just checking to see if anybody might have any useful information or ideas regarding the failure.