Display problem Acer Aspire 5630

The display on my 5630 is dim - not completely dark but probably only about
30 to 40% as bright as it used to be.

Having googled for what causes dim and dark displays in laptop screens
(after making sure it wasn't the lid close switch) I decided to go for the
cheapest things first, so I bought a brand new inverter board. Although it's
definitely the right one, it's actually worse than the existing inverter in
that it strobes a bit. Doesn't do anything for my problem - the screen is
neither brighter nor darker, just a bit stroboscopic. Hmm ...

So, I then buy a secondhand (but guaranteed tested and working) video cable
from Ebay and replace that. Still no change - the screen is still as dim,
whether used with new or old inverter. Hmm again ...

Oh, at this point I should say that I've checked the voltage between pin 1
of the inverter input and ground (which, I believe, should roughly be
between 10 and 20 volts) and got 19.36V - so we know that the inverter is
getting the correct feed from the mobo.

I then look at changing the CCFL backlight tube but (a) can't find one and
(b) even if I could, I've read many horror stories of breaking the LCD panel
whilst trying to change the tube, so I decide to bite the bullet and buy a
whole new LCD panel because they come with a new tube already in them - and
I might as well upgrade from the old matte screen to a new glossy one if I'm
going to do this )

Guess what? Yep, you guessed right - still fekkin' faulty!! Display is still
only at about 30 to 40% brightness - and that's with any combination of
new/old video cable and new/old inverter.

Any other ideas folks?

TIA
John