We must be some of the few people out there who still hold on to the fx-7000g ! I bought mine years and years ago, my first graphing calculator - and if I remember correctly - the fx-7000g was THE FIRST graphing calculator ever made.
I've found that there can be problems with the display when the batteries run low so be sure the batteries are fresh. Also, pull the batteries out and put them back in (reboot).
Next, adjust contrast. You have to tap 'Mode' button and then tap either the left or right arrow buttons repeatedly to adjust the contrast. Other than these I've had no display problems. But...
At about the same time I bought the fx-7000g I also had another Casio programmable (non-graphing) that developed a problem with the display. The symptoms were dimmed or darkened lines of pixels across the display that could be affected by flexing the calculator or banging it into the palm of your hand. I took that unit apart and found that there was a rubber strip with conductors imbedded into it. This strip interfaced the display signals from the board to the display. It seems I may have dropped the calculator onboard ship (back in my Navy days) and this strip became misaligned. After some fiddling I was able to get this strip aligned again. Pressure alone holds it in place. You can also clean it with a soft damp cloth if there appears to be any contaminants in the area where the strip is located.
I've also heard of LCD screens left in the hot sun developing similar symptoms but the effect is usually temporary, with the display returning to normal after the screen cools off. If permanent, despite trying the above, then there may be a power problem in the display driver circuitry, something that is NOT able to be repaired by us mere mortals!
I'm a proud owner of (old) fx-7000g calculator but after years of happy work the display starting to have problems.
Starting from the center of the screen some pixel started to became dark and now this phenomenon is expanded to whole display?
Do you know how can I change the display or fix the problem?
I know this is a very old model but it works fine so why I must trash it if I can try to fix it?