Precision 3550 / Multiple LCD Rail failures

I own a Precision 3550 mobile workstation. Over the past two years, the LCD rail has failed three times (2-8 light sequence, dead screen). Each time the system was repaired through warranty service. The fix doesn't 'stick', and the next time it fails I might not have a warranty.

Time between failures varies. Between 1st and 2nd was about 3 months, between 2nd and 3rd about 15 months.

The computer sits on a desk 95% of the time. Occasionally I'll take it to another room, and occasionally I'll travel with it. The failures have all occurred while it's sitting on my desk.

Support has confirmed that this particular failure isn't common.

I can't see how this wouldn't be considered an ongoing, repeating issue... either some non-replaced component ('the root cause of the issue') keeps breaking the LCD rail. Or I have the worst luck in the world and the replaced components all failed. Dell Support won't consider any of this and I don't understand why. Is it me - am I wrong to feel like this is a repeating issue?