Recently, when I was using my JABE soldering station and changing tips, I heard a pop sound from the unit. Now, the temp idles/sleeps at 30-40 degrees instead of 200, and when active, the power is at 99%, but the tip does not heat up. I can't see anything obviously blown inside, but there appear to be two Fairchild surface-mount mosfets, and possibly one or both are blown. Has anyone else had experience with one of these failing?