I just repaired a 12 years old telephone base station where the LCD display meanwhile turned blank completely. That display does not have pressure contacts but a plastic foil with printed conducting paths which is glued/laminated to the LCD’s base glass and the LCD’s printed circuit board. After quite some time I found out that this foil somehow lost electrical contact, though on visual inspection and mechanically it seemed totally right.
After further experimenting I realized that applying heat of 180°C and pressure reinstalled electrical contact. I used a digitally controlled solder iron with a screwdriver type of tip.
After quite some delicate work with a head loupe I succeeded in getting nearly all pixels work again. Only at three contacts I spoiled it as the tip used was slightly wider than the contact zone, and and at these three contacts I seemingly cut the printed conducting paths of the foil at the point where the foil runs over the edge of glass base plate. So it seems a good idea to chose a tip a little less wide than the contact zone, but not too small (no pencil tip) in order to spread pressure evenly.
I’m curious for how long my repair will last…