I was asked to take a look at an E5500.  This is what I found:  a) a screen that could only be seen with the correct reflected light; and b) outboard screen working perfectly.  This is what I did:  a) tried a known replacement inverter board and this didn't solve the problem; b) tried a known working LCD screen and this didn't work; c) checked the video cable and it looks fine; and d)  since there's no screen switch that might be stuck and I'm assuming that all functions are software controlled, I did a clean install of xp pro.  Still no good.  I looked for a SMD e.g. a fuse and found none.  Would someone please give me some ideas?  Thanks very much!