I just thought I would share some info I came across. I had and old (1980's) depth
gauge that had a very dim display. I was thinking about having to replace it when I came across an article about an easy possible fix.
Most displays use layers of polarizing film. The outer layer often gets damaged by exposure to the sun over the years. Someone wrote in another forum about replacing the old film and their display looked bright and sharp.
I did a little research
on how LCD displays work and why you must have a layer of polarizer on the front for you to see anything. I took apart some old laptop
computer screens and removed the front layers of plastic film. I was not sure which layer was the polarizer, but it was easy to find out. Hold the sheet in front of your computer screen
, or tablet. When you rotate the film you can get the display to go dark and eventually disappear.
I took a peice down to my boat and held it front of the bad gauge display. I twisted it around until I saw a nice bright display. I then took the gauge apart and peeled off the old film and stuck on the new film at just the right angle of rotation. I now have a nice bright easy to read display again.
I think you can buy small sheets
of the film for iphone screen repairs
and such on line if you don't want to take apart an old laptop
This may not fix your problem, but it did for me. I am glad I stumbled across it. Do a google
search and I am sure you will find more in depth