For last some days I have been noticing that there are blank vertical lines appearing across the display screen of my TI calculator. The google search didn't help me much though other people seem to have the same issue. Sometimes, there are appearning four lines and sometimes as much as nine; some of them change their location on turning off and on the calculator. What do you I do? I don't think any local technician would be able to fix it. Please help me. Thanks.
It's missing pixel rows, or pixel columns. It's a common fault.
Sometimes you can fix them by carfull disassembly then VERY carefully clean the tiny rubber strips that join signals from the PCB to the glass LCD. You also need to clean the pcb contacts and the LCD contacts. A touch of alcohol, or 50:50 alcohol and water and very gentle rubbing with a soft lint free cloth.
I had a TI calc that did the same, I was able to get it going twice with strip and clean, but after a few months it got too bad and was unfixable after that, I believe it's caused by a continuing corrosion of the contacts, probably on the LCD glass...