X200 with strange backlight problem.

[FryPpy]

Once upon a time... i have bought X200 (7458-87U) from ebay. Seller have stated that it have X200s display (and on the photos it have WXGA+ one) and it have backlight problem. It have arrived to me and yes no baclight;( But when i have transfered it to X201 it lights up and works ok till now. I have forgotten about that X200 for some time. Made second X201 frankenpad with X200 CCFL lid and AFFS WXGA LCD.
And today decided to investigate what is wrong with that poor X200. I thought that one fuse have blown up. I have found WXGA LED LID from one of these X201 for experiments. Put it ontop of X200 and it lights up and works. But it have one serious glitch. Heavy flickering on any backlight levels except higher. It flicker in any environment - on BIOS screen and when showing Ubuntu desktop. I haven't tested yet it with windows.

What is this? I think original X200 LID have CCFL LCD and flickering wasn't so noticeable. I can disassemble IPS X201 frankie and test it (CCFL IPS with this X200) but only on next weekends. Have you any experience with X200 with X201 LED LCDs?

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Addendum
I have got another X201 lid with LED backlight LCD and placed it on top of this X200. And it works fine - no flickering and brightness works fine in all range. The flickering LID works fine on top of X201 (no flickering on X201). Very strange glitch. I don't know what LCD models are in these lids.