Thinkpad W500 display - brightness (again?)

[planetf1]

I have a Thinkpad W500 Model: 4061-BM6

Running Windows 7 x64 with latest Lenovo Video Drivers ie http://www-307.ibm.com/pc/support/site. ... MIGR-73641.

Brightness is on FULL yet when running on mains or battery display is TOO DIM.

Measures as approx 51-60 LUX [cd/m^2] (not professional calorimeter)
Comfortable is 120-140 which is what my desktop monitor at home AND in office measures as do colleagues W510s (no W500 to check) & commonly accepted on internet

http://shop.lenovo.com/ISS_Static/merch ... asheet.pdf lists the screen as "200+ nit" (1 nit is 1 cd/m^2) The display was never bright but seems to be getting worse and causing viewability issues (headache etc) Believe screen/BACKLIGHT is faulty.

I have a samsung 1920 panel-
a) Is my assertion that this is a HW fault above reasonable?
b) Am I correct that the screen should be 200 nit (I did see 180 mentioned elsewhere)
c) Is there a known issue ?
d) Is there an EC change / specific part number I should be pressing for ?

I should add my lux values above are not from a professionally calibrated system -- I don't have access to one, but should at a minimum be relative & do seem to be fairly consistent with published specs of the other systems I checked.