On Sun, 02 Mar 2014 12:55:11 +0000, N_Cook wrote:

Cause and any amelioration, short of draining the liquid and starting
again (for elfin safety in nothing else), and of course unobtanium
replacement displays

Where I used to work a batch of early large LCD display Philips DVM
meters for the engineers.
Every now and then , despite warning labels, someone would leave one in
direct sunlight (UK version)

heh

for a while and the display would become
next to useless, permanently.
Presumably the LC migrates out of its assigned wells and does not go
back in them. Anyone know of a localised heat/cold/pressure treatment or
something like that ,at least, won't make matters worse , and may
actually improve the splodge a bit?

That's been a problem with older LCD displays on Fluke DMMs as well.
My old 8050A is starting to exhibit those symptoms, despite having
been indoors all of its life.

It's ameliorated somewhat on mine when the display is energized for a
few hours; the dark areas retreat and become somewhat dimmer. Not a
permanent solution, but you might try that. Hook one up to an external
supply (they are battery powered?) and let it run over a weekend to
see if there's any improvement.

There are several hacks around the 'net where folks have replaced the
LCD module with a bank of 7-segment LEDs. What I'll probably try is to
fit an EADog 1x8 LCD module in place of the original, with a small
micro to handle the display initialization and character translation.
The EADog is 55 x 31 x 2 mm, a good fit for the 8050A.