Did you happen to find an LED version that works or a replacement bulb option? Have the same issue with mine where the screen seems to work fine but is dim.
In case anyone else runs across this topic looking for Libretto 50CT/70CT RAM, I found a few other part numbers and some other info.
Other model numbers (16MB):
T2056 (Viking)
RT2056 (Viking)
MGV R60429 T16L1B (or T16L18 -- not sure) (via ebay images)
I also can't find this on MGV's archived...